Reality Factory

I have the newton physics engine and I really want to know how to make a mountable vehicle using the engine.I saw the demos frederico made,but there you start with a car,my game is an FPS I want to get in the car whenever you want.a long time ago I patched my source folder with something (I don't remember what) and in the entities there was something like a Physics Vehicle Entity or something like that.Can that entity be used to make a mountable vehicle using Newton?And if yes where can I find it?