I had some 'difficulties' with mixed and conflicting messages from VicRoads' staff when bringing in a Tasmanian registered bike (XT 600, not that should make a difference), and registering it in Victoria.
There was some disagreement between VicRoads' Bundoora office staff on whether or not I needed an RWC to register the bike in VIC. It didn't really matter in the end as the rego transfer in VIC is the catalyst for a RWC.
IMHO, I think it would be best for an interstate owner (if coming to live in VIC as indicated by the OP) to bring the bike to VIC, keep the bike in his ownership and transfer the bike rego from interstate to VIC (my understanding no RWC required at this point). Some administrative, rego, TAC and plate fees would apply, these could mount up to ~ $600 or $700, but could be off-set with a refund on the balance of interstate fees.
The bike should be easier to sell in VIC than in SA (bigger market), certainly if it has 12 months VIC rego. A RWC would be required on transfer of rego in VIC. This can be obtained by the seller or the buyer. If the seller doesn't provide a RWC, he should remove the rego plate and send / take it to VicRoads. VicRoads will generally send the plate to an office nominated by the seller (usually the closest to the buyer) for the buyer to pick-up once the RWC is presented to VicRoads and fees are paid.