Is it possible have working headlights on units in this game? I figured out how to make Night maps but I wonder if I could have a unit with headlights or lamps that acutally illuminate the map.

Not that actually illuminate the map, but that act like they are, you make a plane and draw the light meshings to that plane which will be a semi-transparent object via Alpha Blends, this object will have a light image on it, applied with the Alpha Blend of course. The light meshings will have a headlight image applied to them in the same manor, and there you have a head light that acts like it's working, but really isn't.

yeah what vanguard said.. and use meshadditive.fx Thats what its for ^^