I've just finished installing the Hepco Becker touring kit on my GT. It wasn't perfectly simple, since tolerances seem to vary a lot on the Ducatis, but the HB mounts have some tolerance forgiveness built in, which helps.
The HB Panniers are NOT compatible with the Ducati Luggage Rack. The Panniers may not work with other sport classics than the GT (due to using the muffler/passenger peg mounts), but I'd be surprised if the luggage rack doesn't work for the dual shock versions of the Sport.
I've attached the instructions below, for reference.