Another button question

I am trying to make a button, when you rollOver it, animation start to play.

I try to insert animated movieClip into button, but in Flash 8 you can’t do that.

I have try with ActionScript to call the animation to play when mouse is over, but also nothing.

Can somebody give me code or where can I found some button, when you go over it with mouse, that animation start to play.

Thanks