Ok, your question give me the clue needed…
It may be the extension installer that do that… not really sure, but there is a maya 2014 folder and a 2014-x64.
I have edited the maya.env in the “2014” one…. and then it did not work…
So i just copy the maya.env file in the “2014-x64” folder replacing the one already in place and tadaaaaa!