I'm looking to buy a frog2 at the moment, getting my first demo on one in the flesh soon, and have been reading through the manual. I can't see any way to assign sound to light directly to a cue/channel, most useful for intensity/dimmer if you wanted the brightness to directly relate to the volume/beat.
I also spotted this:
http://support.zero88.com/forum/index.php?showtopic=4221
which seems to be effectively asking for the same thing, though perhaps he would want the intensity set via fader, and then the sound to light to toggle that on/off so it flashes between off and the fader level on the beat rather than "throbbing". Hope that makes sense . As an atomic owner myself, I'd like to see this too.