Ok, this version (largely untested, so please keep your old executable as well) adds onAttractEnter, onAttract, and onAttractExit animation types. You can use this to set your volume to 0 using onAttractEnter and back to 1 using onAttractExit animations. Do keep in mind that the other animations still work in attract mode, so if you use volume control to fade-out/in volume during game change this will also happen during attract mode.
Something like:
<onAttractEnter><set duration=".2"><animate type="volume" to="0"/></set></onAttractEnter>
<onAttractExit><set duration=".2"><animate type="volume" to="1"/></set></onAttractExit>