Wish I had a scanner to use, cause I do have the diagram.
Yours is the single vacume pod right? My pic shows no one way valve, just basically from your vacume port on the motor into the switch then from the switch straight to the vacume pod. There is not even a tee for using the crossmember as a vacume tank. This is probably because of the vacume pulling the lamps down instead of up, like they do on my S2. The one way valve and vacume reservoir aren't necessary cause really who cares if the lamps creep up as you are driving, the important thing is that they stay up when you need them to, and for you that is accomplished with the spring on the vac pod.
Mind you I have never looked at your setup, so I might be missing something..