ActionScript 3.0 :: Drag And Rotate Function On Mousedown

I'm trying to create a script that would imitate an old rotary phone dial. I have this script, but need it to function on MOUSE_DOWN:

Code:
handle.addEventListener(MouseEvent.ENTER_FRAME, startRotate);
function startRotate(e:Event):void {
var dx:Number=mouseX-handle.x;
var dy:Number=mouseY-handle.y;
// presupposes position of object to be facing to the right.
var radians:Number=Math.atan2(dy,dx);
handle.rotation=radians*180/Math.PI;
var hR:Number = Math.round(handle.rotation);
rotationA.text = String(hR);
}

Changing the event handler doesn't work. Somehow the MouseDown function should be working like an EnterFrame event, I guess. The condition I want to check is whether or not the handle is at a certain degree angle to stop the dial from rotating.
if (handle.rotation >= 30) {
handle.rotation = ?;
}
Not sure what I need to put in there to stop it from rotating.