Toshiba HCI Hotkeys for Linux
This may very well be obsolete by now, but for the sake of sharing... here is the code to support Toshiba HCI hotkeys on Linux systems.
It is implemented as a patch against acpid-1.0.3 (which most likely needs updating for the current version of acpid), and a user-space daemon called toshkey.
It enables the brightness controls, provides battery life information in the system
ps output and allows you to run a script for each of two user defined hotkeys and also in the event of a low power condition.