Adjusting LCD-screen backlight on HP-laptop

[Nimo]

I buyed a HP Pavillion dv2222 some month ago and nearly all things are up and running with Gentoo now except for the keys to adjust the backlight of the LCD-monitor. If I modprobe the video module I get the /proc/acpi/video/VGA/LCD/brightness available and are able to echo different values to adjust the backlight.

The problem is that I don't want to bind static values to different keys, instead I want to use the button dedicated for the task (Fn + F7 and Fn + F8) to increase and decrease the backlight dimming more smoothly.

The keys are doing BIOS calls and works perfectly everywhere outside Linux so I think Xorg maps the calls from the keys or the kernel itself. Are there some way to forward the calls to the BIOS?

Any help that would help me change the backlight in some smoother way than echoing different values to /proc/acpi/video/VGA/LCD/brightness would be greatly appreciated!