Now THAT was easier.
I've been changing my own tires ever since I got my 929, and with 56k on it, I've changed quite a few. I've always struggled getting the rear axle back in.
Tonight I did it slightly differently, and it was much easier. I'll try to explain the procedure I used.
Lift up the rear wheel and press it forward against the swingarm, put the chain on. Start the axle through the left side of the swingarm, pull the wheel back so the axle starts into the wheel. Slide the axle through until it's supporting the spacer on the right side of the wheel, with the wheel as far to the left as it can go. Now put the caliper and bracket over the rotor, checking to be sure it's in the slot. Push the axle through all the way and it's done (well the hard part's done anyway).
I hope this helps someone.