How to launch MS Connect Edition in OS language (or english at last)

Dear all.

Hopefully someone is able to help me with my weird language issue:

I just deployed the latest version (U11) of MS CE to some clients, silent install via sccm including the main setup in english as well as the german language pack afterwards.

I wonder why MS doesn't launch in the OS language on first launch like normal apps would do? It seems to launch always in "de" , most properly due to the installed LP. 

-> "MS_CULTURE=en"   seems to be  also ignored. Still launches in german. Switching languages in the preferences works but Bentley could explain chinese workes how to switch from German to English, I would not .

How is this initial launch language been set? I need to modifiy that to english or better to the OS language (as said, normal professional better quality apps do so) I can see some variables been set like _USTN_LOCALE_LANGUAGE which are locked. Maybe Bentley trie sto get the OS language but has trouble to get this language correctly?

By the way. The mighty great bentley Connection Client (everybody loves it) is able to launch in the OS language by default. Thats great.

Thanks and best regards