How to set a specific level for screen brightness on Storm 9530
 

I am having storm 9530 (OS 5.0.0.328). I want my screen brightness to be contant throughout.
I have changed my settings to:
Screen Brightness: 20/100
Backlight timeout: 20sec
Automatically Dim Backlight: ON (I have also tried OFF)

It works great in low light conditions but when I go out in sunlight the screen brightness becomes more.
Is there any setting to fix it or any application ?