For the TX2000 only 2 of our 4 bezel keys show up in xev. The TX2500 is about the same, 1 of 3? Anyway we bind rotation to one of the working keys, we've nicknamed it the Q key.
Apparently the wmi or hp-wmi needs to be coded for the missing keys. Red_Lion was on the track for that and looked like he was getting close to figuring it out.