Automating buttons

1

I am using a animated MC as a button instance to use a effect of sliding in and out on RollOver and RollOut, however I am trying to add buttons within this MC and when I add them they are not triggering. Any ideas?
Here is my AS: which animates the button tab however the buttons within the MC dont work.


[LEFT]soundtab.onRollOver = over;
soundtab.onRollOut = out;

function over() {
 this.gotoAndPlay(2);
}
function out() {
 this.gotoAndPlay(15);
}[/LEFT]

Any help is greatly appreciated.
Thanks,
MT