OK, the kit finally came through, so here's how it went. The instal was super easy, with the engine supported on a jack. I've written up a How To (
http://www.ducatimonsterforum.org/index.php?topic=70929.0).
Here's the bike with the structural rod in place, but the hangers left off:
I think it looks pretty tidy. The hangers then just bolt on with four bolts (two each side):
I'm very pleased. I will probably leave them off most of the time, to keep the back looking clean, but can stick them on to take a pillion in a couple of minutes. Thanks to everybody for their help and advice.