Reverse the MC!

OK - I’m been searching the forum, and found some useful information, but I still can’t get it to work the way I would like it to.
Here the thing, I’ve made a simple animation and ONE button. When you RollOver the button the animation STARTS to play, and when RollOut the animation plays backward (prevFrame)…

I’m kinda stuck here, found alot of useful code in here, but I can’t figure out how to put it together so it will work my way!

So ANY help would be NICE!

Oh, and BTW the animation needs to be stoped at the last frame!