Controlling the backlight in the registry?

[Guest Alex_le_brit]

I've noticed in the registry there's two different keys for the backlight control, one is for when the phone's on battery power, one for when it's on "mains" power - for instance in its cradle.

Has anyone managed to alter these so that the backlight stays on for different periods of time depending on power source. Ideally I'd like my backlight on permanently on "mains" and on for say 30 seconds on battery.

Anyone done this or be able to guess how to?