Fading an audio channel in CS3

Does anyone known the actionscript 3 code for fading an audio channel over a specified time for example 1 second.

Im struggling to find any information anywhere on this topic, i want to activate the fade with a mouse up event, i think the channel has to be faded with the sound transform property but im unsure, in new to as3, any advice would be appreciated.

Thanks

Liam.