I am guessing that the file I found ( via_audio_10500B.zip ... google for it ) is a beta that will be released officially pretty soon so you may want to want until out officially from asus support site.
After installing it and restarting I see this in device manager for the Via High Definition Audio
Driver version: 18.104.22.16800
Driver date: 5/4/2012
Driver Provider: Via TEchnologies Inc
Now this time around the Via HD Audio Deck works ... I can play something in Itunes and use either the windows volume control and/or Via HD Audio Deck to change the sound level ... and guess what ... the sub woofer volume adjust down up automagically!
I have not done much testing and to be sure we need to make sure that none of the weird things with headphones triggers strange behavior ... but it looks like we are either fixed or getting much closer.
Thanks asus and via ... and thanks to the guys posting here who were hinting that a fix was in the works.
I think the status at the moment is still "not quite officially released" ...