How to change cursor on roll over function

I'm making a point and click game in AS3 with flash.

I've changed the skin of my cursor by creating a new class "Souris". It's working just fine. Now I'm trying to change the skin of the cursor when it's on an object on the scene.

I've read that the MouseEvent.ROLL_OVER is the good method but I can't figure out how to do it...

I've got my Souris class like that :

public class Souris extends MovieClip
    {
 private var engine:Engine;
        private var stageRef:Stage;
        private var p:Point = new Point(); 

        public function Souris(stageRef:Stage)
        {
            Mouse.hide(); //make the mouse disappear
            mouseEnabled = false; //don't let our cursor block anything
mouseChildren = false;

            this.stageRef = stageRef;
            x = stageRef.mouseX;
            y = stageRef.mouseY;

            stageRef.addEventListener(MouseEvent.MOUSE_MOVE, updateMouse, false, 0, true);
            stageRef.addEventListener(Event.MOUSE_LEAVE, mouseLeaveHandler, false, 0, true);
            stageRef.addEventListener(Event.ADDED, updateStack, false, 0, true);
            stageRef.addEventListener(MouseEvent.ROLL_OVER,hover);

        }

        private function updateStack(e:Event) : void
        {
            stageRef.addChild(this);
        }
        private function hover(e:MouseEvent😞void {
souris.visible = false;
}

        private function mouseLeaveHandler(e:Event) : void
        {
            visible = false;
            Mouse.show(); //in case of right click
            stageRef.addEventListener(MouseEvent.MOUSE_MOVE, mouseReturnHandler, false, 0, true);
        }

        private function mouseReturnHandler(e:Event) : void
        {
            visible = true;
            Mouse.hide(); //in case of right click
            removeEventListener(MouseEvent.MOUSE_MOVE, mouseReturnHandler);
        }

        private function updateMouse(e:MouseEvent) : void
        {
            x = stageRef.mouseX;
            y = stageRef.mouseY;

            e.updateAfterEvent();
        }

    }

}
}

In my main class (Engine class) I've got :

private var souris:Souris;

public function Engine(){



                        souris = new Souris(stage);
            stage.addChild(souris);

        }
private function startGame(e:Event😞void{
....
..

I've tried to put in the "Souris" class

stageRef.addEventListener(MouseEvent.ROLL_OVER,hover);

private function hover(e:MouseEvent😞void {
Engine.souris.visible = false;
handCursor.visible = true ;
}

But It seems wrong... I don't know what to put in my hover function.. (I've got the "handCursor" in my library).

Thank you very much for your help !