While cruising at 10,000 feet the pilot reported that the right generator warning illuminated. He reset the generator and monitored its output. After an estimated 5 to 10 minutes of normal operation the right generator warning again illuminated. Simultaneously, the right engine fire warning activated and other warning lights illuminated. Several circuit breakers tripped. The pilot reported that he was unable to select right engine fuel cut off with the condition lever and could not feather the right propeller with the propeller control. He activated the right fire handle, transmitted a PAN and advised ATC that he was diverting to Young. The pilot was unable to land at Young due to fog but Cootamundra was reported clear. Approaching Cootamundra the pilot transmitted a MAYDAY due to smoke in the cabin and requested emergency services. He positioned the aircraft for an approach to runway 16 and selected the landing gear down but did not get any indication that it was down and locked. He warned the passengers to prepare for a belly landing and lowered full flap. Before touchdown he selected both propeller levers to the feathered position. The aircraft touched down on the extended right main landing gear and skidded along the runway on its nose, left engine nacelle and right main landing gear for approximately 400 m. It came to rest with fire in the right engine nacelle still burning. SIGNIFICANT FACTORS: 1. Vibration from the worn armature shaft of the right starter generator resulted in a fractured fuel return line. 2. The armature shaft of the right engine starter generator failed in-flight. 3. Sparks or frictional heat generated by the failed starter generator ignited the combustible fuel/air mixture in the right engine accessory compartment. 4. Items on the engine fire emergency checklist were not completed, and the fire was not suppressed. 5. The operator’s CASA approved emergency checklist did not contain smoke evacuation procedures. 6. The pilot did not attempt to extend the landing gear using the emergency gear extension when he did not to get a positive indication that the gear was down and locked. 7. The aircraft landed on the right main landing gear and slid to a stop on the right main gear, left engine nacelle and nose.