Button rollover effect

1

http://img249.imageshack.us/img249/9…angaur5.th.jpg

So when i roll over the button home, I want the blue bar to slide over to the other side of it.
And when i roll off it slides back, I know how to do that but.
When i go to archive. How cna i make the blue bar go down to that word then slide over?

this is my code for buttons right now

import mx.transitions.Tween;
import mx.transitions.easing.*;

var mc_arr = [Home_btn,Me_btn,Archive_btn];
var counter = 0;

function tweenIn_intro(target_mc:MovieClip){

var image1_a:Tween = new Tween(target_mc, “_alpha”, Regular.easeIn, 0, 100, .5, true);
image1_a.onMotionFinished = function() {
counter = (counter < mc_arr.length-1) ? counter+1 : mc_arr.length;
tweenIn_intro(mc_arr[counter]);
};

}

function tweenIn(target_mc:MovieClip){
var image_rollon:Tween = new Tween(target_mc, “_alpha”, Regular.easeIn, 100, 20, 1, false);
}
Home_btn.onRollOver = function(){ tweenIn(this); }
Me_btn.onRollOver = function(){ tweenIn(this); }
Archive_btn.onRollOver = function(){ tweenIn(this); }

function tweenOut(target_mc:MovieClip){
var image_rolloff:Tween = new Tween(target_mc, “_alpha”, Regular.easeIn, 20, 100, 1, false);
}
Home_btn.onRollOut = function(){ tweenOut(this); }
Me_btn.onRollOut = function(){ tweenOut(this); }
Archive_btn.onRollOut = function(){ tweenOut(this); }

tweenIn_intro(mc_arr[counter]);