yup UDK generate unique uv's is like making a second set in maya. Never lit a night scene but maybe a dominant directional light on low brightness might give the moon lit feel. Lighting is a whole another beast :)
I could knock up darker, but still lit room to help break it up fairly easily. I may even be able to use the current ones but have it lit rather than full bright unlit like the current ones.
One more thing... You're including your cubemap reflections in your customlighting input, so you don't get reflections (and apparently metallic surfaces are only "lit" by the cubemaps?) on surfaces that aren't facing a light source. It doesn't really make sense that a surface would have to be lit directly to have indirect…