Access button inside MC on stage

Question

I have a movieclip on the stage (MC_01) that has a button in it (btn_tip_ows). I need to to get it to work from the main timeline.
If I place the button on the main timeline, the following works.
btn_tip_ows.addEventListener(MouseEvent.ROLL_OVER, rOverowstip);
btn_tip_ows.addEventListener(MouseEvent.ROLL_OUT, rOutowstip);
function rOverowstip(event:MouseEvent):void {
Tweener.addTween(mc_tip_ows,{alpha:1, time:.5, transition:"easeInOutQuad"});
function rOutowstip(event:MouseEvent):void {
Tweener.addTween(mc_tip_ows,{alpha:0, time:.5,  transition:"easeInOutQuad"});

Answer 1

I still get the error 1120. This is what I have:
    On stage: MC_01 and mc_tip_ows
    btn_tip_owsis inside MC_01
mc_tip_ows can go inside MC_01 if needed.
My current code:
mc_tip_ows.alpha=0;
MC_01.btn_tip_ows.addEventListener(MouseEvent.ROLL_OVER, rOverowstip);
MC_01.btn_tip_ows.addEventListener(MouseEvent.ROLL_OUT, rOutowstip);
function rOverowstip(event:MouseEvent):void {
Tweener.addTween(mc_tip_ows,{alpha:1, time:.5, transition:"easeInOutQuad"});
function rOutowstip(event:MouseEvent):void {
Tweener.addTween(mc_tip_ows,{alpha:0, time:.5,  transition:"easeInOutQuad"});
Thank You for any help.