Hello Tim, found you at last thanks to OzzyO use the rivet, thats what it was intended for. Put a bit of cigarette rolling paper in between the washer and the coupling rod, this will stop any solder getting through to the coupling rods.
Re Instructions I agree with you, I have found quite regularly the written refer to parts that don't appear on the diagrams, sometimes they appear about 3 pages on from the one I'm working from.
Grasshopper