I saw this machine several ago, and if you contact the guy he may be able to give you some details.
http://www.garageofxanadu.com/bikebios/garageix.html
Because our bikes use the engine as a stressed member, there's no frame surrounding the engine for the hack to bolt to. As I recall, the setup on this bike involved metal brackets running under the engine, probably from a crosspiece attached to the peg area, and bolting to the case at the bottom front (where case savers usually attach) and then up to the steering head.  This provided 3-point attachment for the sidecar. It looked like a fun rig, and can you believe someone GAVE it to him?.  He said it was a friend who had just bought a Harley.