Child MCs in Buttons

Hello. I’m building a play/pause button for my movie, and here’s how I have it setup:

[LIST=1]
[]The main button object is playPause_btn
[
]The first layer of the button has a movie clip with the pause graphic, named pause_mc
[]The second layer of the button has a movie clip with the play graphic, called play_mc
[
]On the button’s click event, I want to set one of the graphics to 0 alpha and the other to 100 depending on the state, so only one graphic will show through
[/LIST]

The problem is, for some reason ActionScript returns UNDEFINED when I try to reference playPause_btn.play_mc – and when I do a dump of the movie’s objects, I see entries for _level0.playPause_btn.instance12 and _level0.playPause_btn.instance13 instead of the play_mc and pause_mc objects. Why aren’t the objects’ instance names accessible??

Any ideas?

Thanks,
-Nate