Listbox easing

Hi Guys

I was trying this code so that i can scroll a list box with easing but right now only the scroll bar moves with the easing function but not the text in the list box

Weird

on(release){
var easeType = mx.transitions.easing.Strong.easeInOut;
var time = 10;
var dist = 10;
var chartTween = new mx.transitions.Tween(mainMenu_listBox, “vPosition”, easeType, mainMenu_listBox.vPosition, mainMenu_listBox.vPosition+dist, time);
}