My laptop is Toshiba Satellite A660, my backlit keyboard working on Windows7, but how to make it work with Ubuntu 12.10 ?
Unfortunately, it seems that Ubuntu has identified this problem and offloaded it to the Linux team to fix: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/683133
Page 4 of this ubuntuquestions thread mentions the bug in ACPI module. Some people have gotten the backlight to work by disabling ACPI in the BIOS, but that poses its own problems, not least of which is the loss of battery information.
The forum investigators verified that the problem is in fact with the kernel:
You should register yourself as affected on the launchpad page, and hope someone has the kernel smarts to get things working.