diff --git a/htdocs/webservices/server_invoice.php b/htdocs/webservices/server_invoice.php
index 8f14be1a8b9..2150017577b 100644
--- a/htdocs/webservices/server_invoice.php
+++ b/htdocs/webservices/server_invoice.php
@@ -789,7 +789,7 @@ function updateInvoice($authentication,$invoice)
 					{
 						// Define output language
 						$outputlangs = $langs;
-						$order->generateDocument($invoice->modelpdf, $outputlangs);		
+						$object->generateDocument($object->modelpdf, $outputlangs);
 					}
 				}
 				if ($invoice['status'] == Facture::STATUS_CLOSED)