I was struggeling with the backlight quite for a while now. But finally I found something which finally works.
First you need git core installed
sudo aptitude install git-core
Next you checkout the module
git clone git://git.myrix.net/pana_acpi
The next step is compiling and loading the module
cd ./pana_acpi
make
make install
modprobe panasonic_acpi
At this point you can already check if the brightness buttons are working.
Next copy ./pana_acpi/acpi/* to /etc/acpi
and restart the acpid daemon.
/etc/init.d/acpid restart
This module should work on all the 7-Series from Panasonic. I only tried it out with my CF-R7.
