I need help with an idiot question. I've recently bought a 1999 Ulysse with alloy wheels. The wheels are fitted with locking bolts, one per wheel, which I assume was an option. The locking bolts are more recessed in the wheel than the other 4 bolts and have what I assume is a metal cover. With the car came a black plastic tray containing the 4 replaced standard bolts, the metal 'key' with 3 protruding lugs, a black plastic 'adapter' with a hole in the top and another black plastic bit which seems to fit through this hole and finally an empty slot.
Can anyone tell me how to remove the locking bolt cover and what is missing from the tray?
Many thanks.
Sean