1. Flash Lulz Kernel Build 12 or higher
2. Download lights.PRODUCTNAME.so from creams' github
3. Rename so file to lights.GT-I9100.so
4. adb push lights.GT-I9100.so /system/lib/hw/
(backup the original lights.GT-I9100.so yourself)
6. Download BLN App by neldar from Market
BLN App Pro provides more special functions.
Thanks to creams, neldar