Now all you have to do is highlight the layer containing your mask shapes,
and go frame by frame with the animation. Whenever necessary, create a keyframe
and delete mask MC's to slowly, one frame at a time, reveal the image underneath
following the pen animation. It is important this part is done last, as it must
go along with the animation exactly. Any changes to earlier work will result
in improper timing here.
email me if you have any questions. bhughes@escribetech.com