Mc follow another mc while scaling

1

I was wondering how to make mc_menu follow mc_box while it scaled (box).
Here is an example of what I mean.

http://www.nooflat.nu (the menu system following the box)

I am a n00b so I’m using this to scale the mc_box:

on (press) {
tween=new mx.transitions.Tween(_root.mc_box,"_height",mx.transitions.easing.Strong.easeOut, getProperty(MC,_height), 250, 3, true);
}