Animate a XML Flash menu

Ok, I have the XML File and a simple Flash menu with simple buttons (just a rectangle with color and the text).

I wanted to know how can I apply effects to either it and the display of the buttons. For example I’m used to create a simple button and onRollOver set an animation to make it change of color. How can I get that to the XML Flash menu?

This is a horizontal drop down menu (submenus goes down). I wanted to make a transition between show and hide of the submenus, like an animation between the two states, to avoid just rolling over the menu and “bang!” there is the submenu… to make it look a little more animated. Does anyone know how can I handle this?