Thanks for your explanations.
Actually, when I'm doing it, if I click on any link inside the embedded menu page, the new page opens inside the embedded frame (and of course I want it to open like a new page). If I add the "_parent" thing, it doesn't work either.
Any clue ?
EDIT : I found the solution ! For anyone facing the same problem, you must add a space between the address of your link and "_parent"