Passat (B5) :: Tail Light And Rear Turn Signal Bulbs Replacement

I need detailed instructions for how to replace the right (passenger's side) rear turn signal bulb socket and the subassembly that holds the remaining bulbs and inserts into the tail light assembly. I've done this once before successfully but now can't seem to make it work now.

Without the subassembly inserted and locked into place with its locking tabs, the turn signal bulb locks into place in its socket, and that socket in turn easily inserts and locks into place in the hole in the outboard corner of the lens through the rear of the lens assembly. However, I can't seem to install both the turn signal bulb in its socket and the subassembly that holds the rest of the bulbs. The two contacts on the underside of the rim of the turn signal bulb socket would indicate that that the socket installs after the subassembly, but then it has nothing to plug into. When it's installed first, I don't see how the bulb would be energized.

The owner's manual of course says to have the dealer handle maintenance in this area.