placing HUD materials on overlays or brushes in the map somewhere will ensure automatic packers include them. since HUD stuff typically has $ignorez, they'll need to be placed out of bounds facing away from the gameplay space somewhere.
alternatively you could put them in a small box disconnected from the gameplay space entirely to ensure they're never rendered anyway - just be sure to put a point entity like a light inside this box too so vbsp doesn't cull it.
you can check packing by setting sv_pure to 2 before loading the map (or return to menu, use 'flush' to clear the cache, and then set sv_pure).
