Trying to adjust HDRI lighting

[vanderloo]

I've tried 3 or 4 different HDR images for my exterior scene and I keep getting a very dark background image. Everything I change brightens up the building but the sky and lighting don't change. I bring the images into the material editor, (VrayHDRI texture), mapped to spherical, dragged it to the dome light texture and the environment slot.

If I change the dome light or Vray sun intensity the building gets blown out but the background stays the same.
If I change the aperture or ISO the image does brighten up but the white trim in the building blows out again, (all blue). Even after changing the subdivs in the dome light. Still blown out.

Tried increasing the overall multiplier and render multiplier in the material and I get a very slight change. After going past 2 in the render multiplier nothing changes. Decreased the inverse gamma and the building blows out and the background is still dark.
So, to end this long winded question, how can I brighten up my background HDR images without over brightening the building?. Thanks

[svetlozar.draganov]

You can use 2 versions of the same texture with different exposure values.
Plug the first version into Background slot and the second-one into VrayDomeLight(invisible) and you can control each of them separately.

[vanderloo]

That sounds like the solution svetlozar. A little confused on how i adjust the exposure values separately though. Assuming I should make a copy of the texture in the material editor. How do I adjust the exposure values from there?
Thanks

[svetlozar.draganov]

Yes, you have to load the texture twice.
The exposure could be controlled via VrayHDRI multiplier parameters or via VrayDomeLight intensity value.