How can I get the Creative Sound Blaster X-Fi Surround 5.1 Pro volume control to work? I've been using the X-Fi for some time on Windows and it works great. However, on my MacBook Pro I can't get the volume control to work.

I see the device in "System Preferences -> Sound" and in "Audio MIDI Setup" and I can switch output to it and it works great, except for volume control. Is it possible to get it to work too?
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).