Calling Parent Class Function problem

Hello, I have 2 Classes
main.as
and
gallery.as

in main.as i’m creating new object for example:
gl:Object = new gal(); // gallery.as class

in gallery class i have fadeOut function that fades out img, i want to make something like event onFadeOut to call from main as .

i want to know when img fadeout is done in main.as.

sorry for my english