HPX 170 Low light Settings?

Does anyone have experience with shooting footage with the AG-HPX 170 in low light conditions? I have looked at various scene file settings but so far much of the video I shoot is very dark. I work in an ENG environment, usually with nothing more than a camera top light. The video I shoot at night generally looks very under-exposed with very BLACK black levels. I have palyed with the various gain and exposure settings. I am looking to see if there might be some video settings that would help bring out the quality in low light. Any settings that you think might help would be appreciated. Thanks.