Flash MX 2004 rollOver/rollOut

[FrictionBoy87]

Okay so I realize this is a big n00b question but I can just never seem to get this right! I have a button, and I want it to fade in on rollOver and then fade back out on rollOut. Sounds easy right? But its freakin not! I don't know what the deal is...I've tried a lot of different things so I was hoping someone could lend me some code that will take my worries away haha. What I was doing was just being like

on(rollOver){
my_mc.play();
}

on(rollOut){
my_mc.gotoAndPlay(8);
}

and at 8 I would just have the frames reversed or whatever. And that works for about the first time but when u go over it fast then it gets all weird and doesn't work right. I don't really know what to do...I know this is a n00b question so sorry!! But I really want to learn!! Hit me back! Thanks