Ya know ....
STOP ****EN USING RADIANT?!
Excuse that "rage" but you could atleast throw a global illumination mapping onto this, using 3ds max and maiets plugins/worldedit, would be atleast something ...
Besides the fact that youd get a bare minimum ammount of collision problems that youd get using radiant.
But faking a global illumination with fsrad? eh ... go kill yourself, thats easier to accomplish.