I also have a Moherboard with SB600 controler with Audio device : ATI Technologies Inc SBx00 Azalia (Intel HDA) [1002:4383] with ALC888 S/T (codec address #3 yeah really!)
Using a linux Codec Dump and Taruga patcher I have AppleHDA with 2 analog and 1 digital outputs and 1 mic input
You should try this good old method, better than Azalia Stereo!
I'm working to have 5.1 but it's not done yet