Wow, that was a quick answer. Thanks a lot.
I tried contacting "asteronimo" but he doesn't seem to be active since last september that is why I asked the question here.
Your method works really well. I just have alignment issues with some shapes because I am not really mastering the move tool ...
Well I have to go see how the boolean operations work now before I ask again for help, or look for a custom plug in developer !
Laurent