Embeded a FLV to a SWF, want to mute all sounds initially

Hi, I am a noob at this, but I embedded a FLV into a SWF, from here, I’d like to make it so that the sound is muted initially, and then there would be a mute toggle button on top of the video that allows the user to unmute. Anyone know how I can do this without separating the video from the sound? Thanks.