Gamma Burn Value

I was wondering if there's a way to change the burn value of the color mapping section. Every time I apply SR to my scene, SR applies a 0.75 value.
I'm using hdri images and want to use 0.25. I tried to edit the settings but don't see any section that might help.

Thanks

Full Build 1.5.1 (18/11/2013)

The original value is 0.25. Once I launch SR, that becomes 0.75
I will install the update and let you know.

Thanks