Yep, Andy, its part of the big (rather heavy!) luggage cover mechanism bar and does indeed hook up onto 2 fittings in the roof area. That means a R75 Tourer mechanism should latch straight in to a ZTT, if it hasn't got the net. Just needs the roof catches.
Must admit though I have never used it on my V6 Tourer. Guess it may be handy if you're transporting dogs (or kids, even !!!).
I'll take some pics tomorrow,
David