In reply to stvredmond:
The point at which the back roping is required is at the end of a traverse to the right and there is a down climb.
1. The leader goes over, quickdraw onto the ring and then has to down climb. Sets up belay just around the corner.
2. Second comes over. Before the downclimb, remove quick draw, thread bite of rope through the ring.
3. Tie figure of eight on the bite, crab onto harness. Undo orginal knot.
4. Second down climbs, effectivley being top roped.
Make sense?
It's a well worth girdle. Just be get there before or check there are no others climbing up first