I use Ex-Link with all my installs, works great.

I use the physics systems server. The xml file is viewable. here is the hex for some commands. enjoy! If you need another specific button let me know if I have I'll add it.

ON 082200000002d4
OFF 082200000001d5
Power 082200000000D6
Volume+082201000100d4
Volume- 082201000200d3
Mute 082202000000d4
HDMI 1 08220a000500c7
HDMI 2 08220a000501C6
HDMI 3 08220a000502c5
HDMI 4 08220a000503c4