Sorry to bump an old thread but I second the request for Paymate.com.au integration into Auctiva's checkout system. I've heard quite a few horror stories involving dodgy buyers and Paypal/CC chargebacks and I would like to start accepting Paymate payments for my auctions. However, simply having the Paymate logo in the listing and not at the bottom of the auction page means a lot of buyers miss it.
Also if it's possible to have separate checkout pages with different payment options for Aussie buyers vs. International buyers that would be great (as the OP suggested). Too often I've had auctions end and overseas buyers trying to send me money orders which cost me more to cash than the value of the item itself.