Using sound

Hi everyone,

I have this problem:

I have a MC playing with its background music.
I have a button with a loadmovie action for another mc.
The mc is a small window which contains a sound on/off button
playing a radio spot.
What i want to do is when the spot is playing the background music of the main MC either to stop or to fade out till the spot
is done.

Hope you understood my problem.

Need help!!!