(Only just noticed this thread) Hmm I've had similar problems actually, I had a prop_static object (a big kind of kart) and it never showed up, though I added a car in which worked but looked kind of stupid because it had no windows.

Try searching on Valve's dev wiki http://developer.valvesoftware.com/wiki/Main_Page

Other good sites:
http://www.iwannamap.com/
If your mapping counter strike: http://www.fpsbanana.com/tutcats/6