Mini210 Backlight dim

Hi guys, do you have an idea how to set the registry parameters to make the
lcd backlight dimmed, but not turn off.
There is an option to turn off lcd backlight after 15,30,60 sec. But not to
dim it.
Thank you.

Write value to /dev/backlight-1wire

Zaolt, I mean to controll the backlight by normal system wince6 manner.
System by default turn off and on backlight based time in registry
settings. By I want to dim the backlight.

Btw. what is the range for /dev/backlight-1wire? 
0 is of :-)
But what is the max value? 100? 256?

0...127 levels, except 0x40 and 0x60 as they are commands

I am able to control the backlight in C#