Hey, I'm running Ubuntu Studio 12.04.1 on a Macbook Pro 5,2
Out-of-the-box, the volume keys on my keyboard work, and show an overlay of the effect they have on the volume in the top right.

Except for the "unmute" command - I get the visual overlay feedback showing that audio 'is' muted, but it has no real effect (audio stays muted) until I manually go into PulseAudio menu, and click "unmute".

So, media keys mute, increase volume, and decrease volume, but do not unmute.

Anyone else with similar problem, or proposed solution?