XPath Constraint on System.User_Language

Hi,

I am trying to add an XPath constraint to a microflow to filter the datasource based on a matching user language.

I noticed that:

• the "App Store modules/Administration/User Management/Admin/Account_Edit/Language/referenceSelector1"

uses 

• System.User_Language/System.Language/System.Language.Description

but I can't:

• create an association from an entity in my module to the "System.User_Language/System.Language" entity
• create an entity in my module which inherits from "System.User_Language/System.Language" entity
• use "[$currentUser/System.User_Language/System.Language/System.Language.Description = ..." in my XPath; as a matter of fact, I can traverse beyond "[$currentUser/System.User_Language"

How do I filter on the User's language?

Any tips are well appreciated,

Guislain