How do you add in "easing" for mouse following masking effects?

Hi all flash experts and experts wanna be out here! =)

I was actually trying to create an easing effect that bases on the movement of the mouse, very similar to:
http://www.kirupa.com/developer/actionscript/scriptable_masks.htm

but unfortunately, I really have no idea how i could actually write an actionscript to create this “esaing” ability…

I have actually attached my own file for your convience, and i really really really hope you guys could assist me in this area!

Thank you so much! :wink: