I'm trying to build a CTF map featuring a truck stuffed full of intel briefcases. I used a playerclip brush to prevent people getting caught on the truck's geometry, then filled the bed with prop_static briefcases. The briefcases, however, don't load when I run the map, and it warns me that they can't be prop_static or prop_detail. Apparently it has to be $staticprop but I don't know what that is and the Valve Dev wiki doesn't offer any clues. Additionally, I want to add a vending machine with a small halloween health kit in front of it... but I don't know how to do that either.