I'm running the CM10.1 nightlies on my Galaxy S2 (i9100). I've purchased the KitSound GALS2Dock, which has audio out over USB, but it doesn't work.
I've asked KitSound via Twitter, and they told me to switch on the Audio Output Mode. I think this is a Samsung specific setting, but I found this in the samsung specific CM10.1 settings menu.
(It says USB-audio dock - use passive audio out from the dock)
I've checked it, and now the phone audio stops (so that's one thing) but my box nor my TV recognises the sound. It does work when I plug it in the regular audio jack.
So I'm thinking this is a software issue. My question: where could this issue be? Is it CM10.1? Is it CM in general (EG: downgrading to CM10 wouldn't help? Or do I need to switch back to a stock samsung ROM in it's entirety to have this functionality work (I'd prefer not to).