The screen capture actor for the Pano capture does not currently take PP settings into account. You can add this but you will have to modify the C++ code of the Pano plugin to get this functionality. I got around this by setting the indirect lighting in my PP volume to a value of 4.0. Give that a try and see if it gives you the results you are looking for. If you want to read more about how to implement the C++ chagnes for the PP check out the blog post ninja theory did about the plugin.
Cheers-
Sam