Sound on a layer for animation - needs mute button

Hi, i’ve made an animation for a friend and need it has a layer with a sound on it for animation and syncage purposes. So the sound does have linkage for actionscript and its also set to stream, but i cant seem to work out how to MUTE or PAUSE the sound using actionscript on a certain frame. there is so far no actionscript used for the sound, it is jsut sitting on the layer.

Any ideas?

Cheers