How can I get the Creative Sound Blaster X-Fi Surround 5.1 Pro volume control to work?
The workaround I found so far is to use Soundflower as an intermediate filter between PC output and the X-Fi. This allows to control volume from Mac OSX at the price of some sound processing. I cannot comment yet on sound quality but on first auditions it seems to sound better than setting the volume to 1/100 in Songbird (my FLAC player).