Motion presets on buttons?

I have a question…I saw on a website once (I wish I could remember which site it was), flash buttons that were creatively animated.

The button would appear just as text, but when you hovered over it, an image would rise from behind it, then, when you moused off, the image would go back down.

It did this for each of the buttons and I cannot figure out how to get that to work, especially since in CS4 with AS3 you cannot use AS on a button.

It’s also really difficult to add a motion preset to a button…can anyone help?

Thanks.