You are probably better off asking in the Actionscript forum or one of the Flash Help forums.
I was looking into this myself and this is what I found so far
Make a movieclip and within that movieclip have the animation you want to play.
Have a stop(); command on the first and last frame of the animation.
Then add this actionscript to the movieclip that holds the animation
PHP Code:
on (rollOver) {
play();
}
on (rollOut) {
this.onEnterFrame = function() {
if (this._currentframe>1) {
this.prevFrame();
} else {
delete this.onEnterFrame;
}
};
}
Only problem is when you rollout and rollover again when its "rewinding" it wont play again.
Its a start but if you need more help ask in a more relevant section. Other people will be able to help you more than me