I'm using Ubuntu 12.04 64bit on a Acer 5750G laptop. Using Unity, I cannot switch my audio output device to the HDMI port of my laptop. The problem is that the HDMI port simply is not shown as an output device in the sound/audio settings, even when a device like a TV is connected to my HDMI port.
Meanwhile under Gnome 3.4, I can select multiple combinations of input and output devices in the audio settings, including combinations that output sound on the HDMI port and thus on my TV.
How can I make Unity to show my HDMI port?