Comment 23 for bug 961286

@Andrei:

( 0.523| 0.000) I: [pulseaudio] alsa-util.c: Successfully attached to mixer 'hw:1'
( 0.523| 0.000) D: [pulseaudio] module-alsa-card.c: Jack 'HDMI/DP,pcm=3 Jack' is now unplugged
( 0.523| 0.000) D: [pulseaudio] device-port.c: Setting port hdmi-output-0 to status no

This indicates that you don't have your HDMI cable plugged in. Or possibly, that there is a problem with your video drivers detecting that you have actually plugged it in.
That's why it doesn't show up. Are you sure it works? If it does not work, the sound settings is doing the correct thing by hiding stuff that doesn't work anyway.