Function scope with different levels

Hi all,
I’m having a problem calling a function from a different level.
I have my main movie ‘Mymovie.swf’ in which I add a level(with loadMovie) with this code:
loadMovie(“MyNewMovie.swf”, “_level1”);
On a button in MyNewMovie.swf, I try to call a function in ‘Mymovie.swf’, by doing:
on(release){
_root.MyFunction();
// or even: _level0.MyFunction();
}
I’ve tried several ways to do it and looked in the forums. Can anybody help me please,
thanks
Danny
Long Live The Web