I have been trying countless combinations of kexts from around the net to get my ALC888 sound working. My computer reports that finally all channels are detected and supported. I didn't need to patch DSDT or anything complicated, just install 3 kexts.
This works for Snow Leopard, Lion AND Mountain Lion! Kexts attached at bottom of post.
I have succeeded with sound by using a HDAEnabler from this topic
And modifying the AppleHDA.kext from this post:
I modified Taruga's ALC888 file by adding a plugin called HDAEnabler.kext inside it. This was apparently the only thing preventing the driver from working, even though I had installed HDAEnabler.kext separately as its own kext and not inside /Plugins of another. Strange, but it works now!
For both functional drives, please scroll to the attachment.
I recommend you use Kext Wizard to install them. I know I can't force you to but it will only increase your chance of success.
Kext Wizard 3.7.10 - Downloads - OSx86.net
Hope it works for you like it did for me! All credit goes to original authors of the kexts ofcourse.