You could try and put a very bright white plane behind the wooden planks that fades out when you get close to it using a pixeldepth material node. Put the colours to 1,1,30 for example to get that cool blue/purple over-exposure. This will not require an overbright sky and is in fact a method used in a lot of games where…
..That isn't what I meant :P UDK doesn't have the functionality to dynamically adjust the output range based on how bright the screen currently is. It doesn't adapt like in, for example, Half Life 2 Episode 2. That is what I meant.