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 956fbfd5..8a327b6e 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
@@ -57,8 +57,8 @@ trait selfserve_lane_invoice_t
             2285, // System User ID
             '',
             '',
-            $this->department_lane->department->id,
-            $this->getLicensePlate()
+            (int)$this->department_lane->department->value(),
+            (string)$this->getLicensePlate()
         );
         // Add product to order
         $order_items = new order_items_o();