I might be wrong here, but I think your book is right.
You say SHAFT which is not the final drive, as such.
I had a s/h 1200GS last year and my warranty book said just that.
Something else to bear in mind with these wonderful warranties is that the dealer will only pay for the labour, and not the parts.
The way I saw it, was that for argument sake a gearbox shaft let go and wrecked the gearbox, the dealer will do the work but charge for the bits.
I think the wording was roughly," the dealer will pay for any repairs covered by the warranty"- on one page, and another " the dealer will not pay for the parts of any repair covered by the warranty".
That's how I construe it anyway.
Good luck.