Hey sumguy,
Sorry for the delayed reply, but I just noticed your message. In short, it has been aaaages since I looked at that bit of code, but it is done by calling a function called LightStyle, found in IVEngineServer. We all learned it from fysh, who did it in nemod, except nemod uses a full dark parameter (check the nemod sources for that) whereas we prefer the 'semi-dark' appearance that doesn't blot out whole models etc.
I'm just starting to learn SourceMod myself, so I'm not sure how it should be done here, but please take a look at how we do it in ZombieHorde. We have always been proudly open source, so you can get our code here:
http://zombiehorde.svn.sourceforge.n...iehorde/trunk/
Look in zhplug.cpp, search for 'LightStyle'
I hope this helps.
.robot