Yep it's a combi brake guys
The disc is mounted on to the front drum. The caliper is held in place by a bracket fabricated out of sheet steel that's around 3mm to 5mm thick. The bracket is held in place by one of the axle pinch (thanks for the word Mpower, i didn't know what to call those) bolts and the mudguard stay bolts. I wonder how the bracket would withstand the forces generated during braking. Poor RD.
pulsarmaniac, is that a Pulsar based Busa? There was an article about a Pulsar based Busa in one of the automags.