Use newly created document after OPCUA request.

bt5/erp5_opcua/SkinTemplateItem/portal_skins/erp5_opcua/ERP5Site_handleOPCUARequest.py

@@ -24,7 +24,8 @@ if default_opcua_document is None:
   default_id = "1"
   default_opcua_document = context.opcua_document_module.get(default_id, None)
   if default_opcua_document is None:
-    context.opcua_document_module.newContent(portal_type = "OPCUA Document",
+    default_opcua_document = context.opcua_document_module.newContent(
+                                                             portal_type = "OPCUA Document",
                                                              id = default_id)
 
 # do selection of operation in a REST fashion based in HTTP method