So.. I give up on my old idea (which you can see it here: http://community.clickteam.com/threads/81622-Drawing-some-object-out-of-a-game-frame-at-runtime)

.. MMF2 seems don't allow that.. oh man...
So, I come with a new question more easy : Is there any solution to have an IMAGE as application background and use it as seamless tile ?

Thanks!