you can sell it with reg, he'll just have to have it cancelled, best to sell it un regged tho, no paperwork that way. i looked into it once for the other way around, NSW-Vic and yeah, you buy the bike and hand in the plate with the xfer papers to get a refund. but you can easily cash in the reg while you've still got it and give them a refund to that value. its essentially the same thing as buying an unregistered bike, they'll just have to get the RWC and take it into uhhh NSWroads?? (

) and get it registered. all you need to provide is a receipt that way