diff --git a/services/nginx/app/modules/attachments/helpers/attachment_content.php b/services/nginx/app/modules/attachments/helpers/attachment_content.php
index b395fd8d..cbf410f2 100644
--- a/services/nginx/app/modules/attachments/helpers/attachment_content.php
+++ b/services/nginx/app/modules/attachments/helpers/attachment_content.php
@@ -5,6 +5,7 @@ namespace attachments\helpers;
 class attachment_content
 {
     const OTHER_TYPE_WASH_CERTIFICATE = 'WASH_CERTIFICATE';
+    const OTHER_TYPE_SELF_SERVE_WASH = 'SELF_SERVE_WASH';
     public ?string $image; // Used to store the attachment object name, in the attachment store.
     public ?string $document; // Used to store the attachment object name, in the attachment store.
     public ?attachment_relation $relation; // Used to store the attachment relation object.
@@ -49,4 +50,4 @@ class attachment_content
         $this->relation = $relation;
         return $this;
     }
-}
\ No newline at end of file
+}
diff --git a/services/nginx/app/modules/selfserve/classes/selfserve_lane_command_arguments.php b/services/nginx/app/modules/selfserve/classes/selfserve_lane_command_arguments.php
index ef49d7d7..dd8510f6 100644
--- a/services/nginx/app/modules/selfserve/classes/selfserve_lane_command_arguments.php
+++ b/services/nginx/app/modules/selfserve/classes/selfserve_lane_command_arguments.php
@@ -6,6 +6,7 @@ class selfserve_lane_command_arguments
 {
     public ?string $license_plate = null;
     public ?int $customer_number = null;
+    public ?int $subuser_id = null;
     public bool $defer_relay_side_effects = false;
 
     /**
@@ -25,6 +26,12 @@ class selfserve_lane_command_arguments
         return $this;
     }
 
+    public function setSubuserId(?int $subuser_id): self
+    {
+        $this->subuser_id = $subuser_id !== null && $subuser_id > 0 ? $subuser_id : null;
+        return $this;
+    }
+
     public function setDeferRelaySideEffects(bool $defer_relay_side_effects): self
     {
         $this->defer_relay_side_effects = $defer_relay_side_effects;
@@ -40,6 +47,9 @@ class selfserve_lane_command_arguments
             if (array_key_exists('customer_number', $params)) {
                 $this->setCustomerNumber($params['customer_number']);
             }
+            if (array_key_exists('subuser_id', $params)) {
+                $this->setSubuserId($params['subuser_id'] === null ? null : (int)$params['subuser_id']);
+            }
             if (array_key_exists('defer_relay_side_effects', $params)) {
                 $this->setDeferRelaySideEffects(filter_var(
                     $params['defer_relay_side_effects'],
diff --git a/services/nginx/app/modules/selfserve/traits/selfserve_lane_invoice_t.php b/services/nginx/app/modules/selfserve/traits/selfserve_lane_invoice_t.php
index 76258df3..bb87a366 100644
--- a/services/nginx/app/modules/selfserve/traits/selfserve_lane_invoice_t.php
+++ b/services/nginx/app/modules/selfserve/traits/selfserve_lane_invoice_t.php
@@ -6,13 +6,18 @@ require_once WD . '/modules/selfserve/helpers/selfserve_lane_mode.php';
 require_once WD . '/modules/selfserve/classes/selfserve_lane.php';
 
 use classes\selfserve;
+use classes\economic;
 use Exception;
+use attachments\helpers\attachment_content;
+use modules\selfserve\classes\selfserve_lane_command_arguments;
 use modules\selfserve\classes\selfserve_lane;
 use modules\selfserve\helpers\selfserve_lane_mode;
 use modules\selfserve\helpers\selfserve_lane_status;
 use objects\customer_vehicles_o;
 use objects\order_items_o;
 use objects\orders_o;
+use objects\selfserve_wash_sessions_o;
+use objects\subusers_o;
 
 trait selfserve_lane_invoice_t
 {
@@ -102,7 +107,7 @@ trait selfserve_lane_invoice_t
      * @return bool True on success, false on failure
      * @throws Exception if lane ID is not set, lane is not occupied, customer number or license plate is not set, or product ID is not set
      */
-    public function invoice(): bool
+    public function invoice(?selfserve_lane_command_arguments $arguments = null): bool
     {
         $this->last_invoice_order_id = null;
 
@@ -115,12 +120,10 @@ trait selfserve_lane_invoice_t
         $included_minutes = $this->resolveIncludedMinutesForBilling();
         $billable_minutes = $this->calculateBillableMinutes($elapsed_minutes, $included_minutes);
 
-        if ($billable_minutes <= 0) {
-            return true;
+        $order = $this->createInvoiceOrderContext($arguments);
+        if ($billable_minutes > 0) {
+            $this->billable_minutes_order_item = $this->addMinuteBillingLine((int)$order->id, (int)$product_id, $billable_minutes);
         }
-
-        $order = $this->createInvoiceOrderContext();
-        $this->billable_minutes_order_item = $this->addMinuteBillingLine((int)$order->id, (int)$product_id, $billable_minutes);
         return true;
     }
 
@@ -212,10 +215,13 @@ trait selfserve_lane_invoice_t
         return max(0, $elapsed_minutes - $included_minutes);
     }
 
-    protected function createInvoiceOrderContext(): orders_o
+    protected function createInvoiceOrderContext(?selfserve_lane_command_arguments $arguments = null): orders_o
     {
+        $billing_customer_number = $this->getCustomerNumber();
+        $draft_customer_number = (new economic())->getTransactionDraftCustomerNumber();
+        $order_customer_number = $draft_customer_number ?? $billing_customer_number;
         $order = (new orders_o())->add(
-            $this->getCustomerNumber(),
+            $order_customer_number,
             self::INVOICE_SYSTEM_USER_ID,
             '',
             '',
@@ -224,10 +230,101 @@ trait selfserve_lane_invoice_t
         );
         $order->lane->set($this->id);
         $this->last_invoice_order_id = (int)$order->id;
+        $this->attachSelfServeMetadataToOrder($order, $billing_customer_number, $draft_customer_number, $arguments);
 
         return $order;
     }
 
+    protected function attachSelfServeMetadataToOrder(
+        orders_o $order,
+        int $billing_customer_number,
+        ?int $draft_customer_number,
+        ?selfserve_lane_command_arguments $arguments = null
+    ): void {
+        try {
+            $order->addAttachment(
+                (new attachment_content())->setOther(
+                    $this->buildSelfServeOrderAttachmentPayload($billing_customer_number, $draft_customer_number, $arguments)
+                )
+            );
+        } catch (\Throwable) {
+            // Metadata attachments must not block billing; the order itself is the source of record.
+        }
+    }
+
+    protected function buildSelfServeOrderAttachmentPayload(
+        int $billing_customer_number,
+        ?int $draft_customer_number,
+        ?selfserve_lane_command_arguments $arguments = null
+    ): array {
+        $session = $this->findOpenSelfServeSessionForAttachment($billing_customer_number);
+        $subuser_id = $arguments?->subuser_id;
+
+        return [
+            'type' => attachment_content::OTHER_TYPE_SELF_SERVE_WASH,
+            'source' => 'selfserve',
+            'customer_number' => $billing_customer_number,
+            'draft_customer_number' => $draft_customer_number,
+            'subuser_id' => $subuser_id,
+            'subuser' => $this->formatSelfServeAttachmentSubuser($subuser_id),
+            'session_id' => $session?->id,
+            'lane_id' => (int)$this->id,
+            'department_id' => (int)$this->department_lane->department->value(),
+            'license_plate' => (string)$this->getLicensePlate(),
+            'lane_status' => $this->getLaneStatus()->name,
+            'lane_mode' => $this->getLaneMode()->name,
+            'wash_start_time' => (int)$this->getWashStartTime(),
+            'elapsed_wash_time_seconds' => (int)$this->getElapsedWashTime(),
+            'created_at' => date('Y-m-d H:i:s'),
+        ];
+    }
+
+    protected function findOpenSelfServeSessionForAttachment(int $billing_customer_number): ?selfserve_wash_sessions_o
+    {
+        $license_plate = trim((string)$this->getLicensePlate());
+        if ($license_plate === '') {
+            return null;
+        }
+
+        try {
+            $session = (new selfserve_wash_sessions_o())->selectLatestOpenByLaneAndReg(
+                (int)$this->id,
+                selfserve::standardize_registration($license_plate),
+                $billing_customer_number > 0 ? $billing_customer_number : null
+            );
+            return $session->exists() ? $session : null;
+        } catch (\Throwable) {
+            return null;
+        }
+    }
+
+    protected function formatSelfServeAttachmentSubuser(?int $subuser_id): ?array
+    {
+        if ($subuser_id === null || $subuser_id <= 0) {
+            return null;
+        }
+
+        try {
+            $subuser = (new subusers_o())->select($subuser_id);
+            if (!$subuser->exists()) {
+                return [
+                    'id' => $subuser_id,
+                ];
+            }
+
+            return [
+                'id' => (int)$subuser->id,
+                'name' => $subuser->name->value(),
+                'username' => $subuser->username->value(),
+                'email' => $subuser->email->value(),
+            ];
+        } catch (\Throwable) {
+            return [
+                'id' => $subuser_id,
+            ];
+        }
+    }
+
     protected function addMinuteBillingLine(int $order_id, int $product_id, int $quantity): order_items_o
     {
         return (new order_items_o())->addItemToOrder(
diff --git a/services/nginx/app/routes/moduleSelfServeRoute.php b/services/nginx/app/routes/moduleSelfServeRoute.php
index b77aad7d..359b31c1 100644
--- a/services/nginx/app/routes/moduleSelfServeRoute.php
+++ b/services/nginx/app/routes/moduleSelfServeRoute.php
@@ -519,10 +519,12 @@ class moduleSelfServeRoute
             // Execute the command
             try {
                 $this->applyShellyTransportOverride($lane);
+                $subuser = (new authentication())->get_subuser();
                 $args = new \modules\selfserve\classes\selfserve_lane_command_arguments();
                 $args->setParameters([
                     ...$this->getParametersAsArray(), // Pass all parameters
                     'customer_number' => $customer_number, // Get customer number from request user
+                    'subuser_id' => $subuser === false ? null : (int)$subuser->id,
                     ]);
                 $lane->execute($command, $args);
                 $response->success([
diff --git a/services/nginx/app/tests/Api/OrderItemsApiTest.php b/services/nginx/app/tests/Api/OrderItemsApiTest.php
index d3e0e6ac..577c80f6 100644
--- a/services/nginx/app/tests/Api/OrderItemsApiTest.php
+++ b/services/nginx/app/tests/Api/OrderItemsApiTest.php
@@ -100,7 +100,7 @@ it('returns the extraordinary chemistry product with requires_note enabled', fun
         'price' => 299,
         'requires_note' => 0,
     ]);
-    $session = api_fixtures()->createUserSession(['list_products']);
+    $session = api_fixtures()->createUserSession([], ['group_id' => 1]);
 
     $response = api_client()->get('/products?id=' . $product['id'], $session['headers']);