[mx2004] Control Main Timeline From Button Inside Movieclip

I’ve created a movieclip with buttons inside that I want to use to navigate to different scenes on the main timeline. I have created a function() that loads the button movieclip into the main timeline, but if I try to write a function() to activate the button and move the main timeline to a different scene/frame label it doesn’t work. I have tried various things:

navBack_mc.book_btn.onRelease = function() {

I put the code above on the main timeline. It doesn’t seem to work. Basically, I could put just an on(release) handler on the buttons, but I wanted to try to keeping all the AS in one place if I can.

Thanks in advance.