Found it .
I did an export of the Belgian regional settings registry key (b.reg) and also for us.reg. I then use a little batch to start my program:

regedit /s us.reg
miatalinklab.exe
regedit /s b.reg

To prevent the dos window from staying open in the background I use a little utility called Quiet.exe that makes it run completely invisible (not even minimized on the taskbar). That way I can't close it by accident before my program has ended.

Perfect !

Frank