Image Mask follows Cursor with fade-in/out

programming flash
1

Hello I am trying to replicate this close up feature on Modavo’s watch website.

http://www.movado.com/Details.aspx?Id=collectionbelamoda&watchType=collection&watchCode=belamoda&watchId=606260&page=0

I looks like the have a large image of the watch, masked over a thumbnail of the watch. Then when the mouse rolls over the stage the mask appears and follows the cursor. When the mouse rolls off, the mask disappears.

My FLA file can be downloaded from http://www.grandtimeco.com/magnify.fla it was too big for Kirupa

So far all I have is:
myMask.onEnterFrame = function() {
var yMouse = _root._ymouse;
if(Math.abs(xMouse - this._x) < 1) {
this._y = yMouse;
} else {
this._y -= (this._y-yMouse) / 7;
}
}

I want to get the mask to appear and disappear when the cursor is over the MC or stage area. PLEASE PLEASE HELP ME!!! Or tell me how to recreate the affect that Movado has for their watches zoom. THANKS AGAIN!!