Hi David,

I know this is no help with your problem, but for a small cost this AddOn
will save you a lot of heartache http://www.intense-i.com/

It sets everything up for you with just a few mouse clicks.

I never liked programming in any of the scripting provided, but I have managed to get three Level's, all looking quit good, but this Addon is only good if you
are making an FPS Game.