DropDown Menu - Using only MCs

I am building a flash menu bar. Quite simply, I want to know if its possible to build the menubar without using button symbols, so i can be a bit more imaginative with how the dropdown is animated.

The scenario:

I create an MC labeled "publications". inside this mc i create two frames. One is the "up" state and one is the "over" state. So on rollover, this "publications" mc will play frame two. In frame two i have a movie clip, which is basically the animation of the menu sliding down with a tween. That movie clip ends at a frame with a stop command and a few buttons at that frame.

The Problem:

For some reason, no MC or Button can be placed on the last frame of that movie clip and actually function. Not sure why this is because it seems like it should.

any ideas? Can i not build a dropdown menu in this way?