I've a solution for the people who want to have hdmi sound with pulseaudio (for example, with ubuntu). It's a very dirty solution, but for me it work great.
I'm running driver 270.41.03 and kernel 2.6.39 (git version under developpement) but it will certainly work with other kernel.
First, follow the official documentation to get the sound working with alsa:
When you have a device working (for example, for me, the command "speaker-test -c 2 -r 48000 -D hdmi:1,1" is working). You have now your working hdmi output.
Then, create a soundrc config file (i create a ~/.asoundrc but it will work with /etc/asoundrc too).
In it, create a virtual device:
The pcm.nvhd is the virtual device but it can handle only one sound by one.
Default device redirect to pulseaudio.
Now edit your /etc/pulse/default.pa
Uncomments alsa sink and give your virtual device:
load-module module-alsa-sink device=plug:nvhd
### Automatically load driver modules depending on the hardware available
### Alternatively use the static hardware detection module (for systems that
### lack udev support)
This will prevent autodection.
Now restart pulseaudio with pulseaudio -k && pulseaudio
You will have a complete working audio system.