The motorcycle mount for the XT is different from the previous Zumo models and the BMW navigation system; the GPS unit itself has larger dimensions than the priors. I was able to configure the XT mount and unit to fit in the "factory-prepared" space of the "Instrument Cover" (part name in fiche). I also spliced the XT power wires into the factory wiring harness, so the on/off power is controlled by the ignition key.
If anyone is interested, contact me for more information, and I can provide pictures.
If anyone is interested, contact me for more information, and I can provide pictures.