Menuitem button on listpage notworking on the Enterprise Portal (ExternalRecord)

I’m developing Listpages in AX 2012   (6.1 CU 2)  and want them as match as possible be EP ready.

But I run in strange things. Menu items to jump from one listpage to another list page. Works fine in AX client but not in EP

 Reason: the externalRecord is empty in the EP runmode.

My menu item button in the Form is as below image

 My code in the class of the target listpage