update : I got some feedback on my mail to M$. One solution is for the mentioned code to add the line : iss2.imbue(std::locale("C"));
--> did not try that one, don't like to change sources, will try it though
The second work around told me to changec xclocnum and xlocmon, but that didn't help me (or I did something wrong), so waiting for the next M$ mail. Hey, they provided quick feedback !!