Virt,
The problem with this kind of animated button, especially when the animation is outside the button and a long one as your's is, is that you have to force it to fade in completely before you can have it fade out, otherwise you get jerks!
In other words, your animation could hold the two actions (fade up & down), with a stop between the two. On rollover you tell target your mc to play the fade up, on rollout you tell target it to play the fade down. But this way there's a problem on a quick rollout after a rollover, since your alpha level might not have reached the 100% level necessary for a smooth fade down that starts from that 100% level!
Dave did answer this question when he designed a button for you called Sambutt.fla. I've looked for it's link in the threads but can't find it. Probably mixed up in one on Sam's threads cause Dave had mixed you guys up that day! Probably another one of those beer & coffee nights! In any case if Dave cant't find it, I have a copy of it I could eventually upload if needed.
Look to see if you had dowloaded this Sambutt.fla and try to apply the same principle. This uses a control mc.
B-)