here's the touring kit I fitted to Andrew's Transalp, the bike he traded in for his Tenere. 35,000 miles later it looked the same:
I bought the touring kit for the Tenere with the intention of attaching it in a similar way to Givi tubular rails, for the wee 24ltr panniers I already had. However, the only rails available for the Tenere are only compatible with their V35 panniers. I've since ordered the Yammie pannier set, but alas no rails to attach the HCR to.
I've had the rear guard off and it has a steel stiffener in it already, to just above the level of the number plate. Below that is as robust as any plastic guard that the touring kit is designed to fit. No mudguard/number plate holder is designed to take it as such, the touring kit is designed to fit the mudguard. Anyhow, stranger things have happened, it might just work.
ps. update 15/12/08 removed touring reservoir and chopped mudguard. details to follow on tenere section.