[ltp] T22: Turning off backlight from xscreensaver?

[Silvio Böhler]

Hardware: Thinkpad T22, S3 Savage IX-MV
Software: kernel 2.6.10, latest ACPI patch, latest ibm_acpi.ko, Debian 
Unstable

Since I have switched my power management to ACPI, screen blanking from 
xscreensaver doesn't turn off the backlight anymore. This used to work 
without problems with APM, it seems DPMS is not working on this laptop 
if ACPI is enabled.

I can sucessfully control the backlight via

echo lcd_[enable|disable] > /proc/acpi/ibm/video

and, using the hotkey feature and some script in /etc/acpi/actions, I 
can toggle the screen with Fn-F3.

Does anybody have an idea how to turn off the backlight from xscreensaver?

Thanks!
Silvio