Didn't Braintree just expand to a lot of countries: https://www.braintreepayments.com/tour/international
(It almost defeats the point of using it at all over one of the existing merchant-account-requiring solutions here.)
(And as zhoutong correctly pointed out above, it's NAB, not Westpac.)
AFAIK only NAB has multi-currency acquiring solution at the moment.
It seems that Braintree's pricing isn't attractive at all, so I'll probably still go for eWay.