I recently installed Ubuntu 12.10,and I can see it in the list of inputs. But when I select it then no sound I have tried restarting pulse audio demon and I have tried purging .pulse and .pulse-cookie directory as well. As I said it is visible in list but after selection no sound I have tried changing the 5.1 and 4.1 as well.
The solution was to unmute a volume control in
More details are here: Howto- Resolve Nosound Problem On Ubuntu 12.10, 12.04 And Older
The problem was not with Ubuntu/PulseAudio. Instead the problem was with the Bose Companion 5 System.
I turned off the Companion 5 system for 20 seconds, using the switch at the back of the subwoofer, then I switched it back on, and voilá! No need to reboot Ubuntu, the 'Bose' output device disappeared and re-appeared during the process, and now the sound is going out fine.
I usually leave the Bose system on 24x7, plugged into a power surge protected line, but for some reason, it seems like it crashed. A reboot of the Companion 5 was the solution.