ActionScript 3.0 :: Add A Title To Button In Flash?

I have a button in flash and a action layer with the following script:
  
button1.addEventListener(MouseEvent.CLICK,clickHandler);
function clickHandler(event:MouseEvent):void{
navigateToURL(new URLRequest("http://mortimerhall.99k.org/homepage.htm"),"_self");
}
 
Now I would like to have a title when user move mouse over a button eg "Click To Enter". I tried this code in a new layer but it doesn't work:
 
on (rollOver) {
text = "hello";
}
on (rollOut) {
text = "";
}