I believe it will not matter. Whilst you are overseas, the credit card will take the country's currency for your transactions and it will automatically do the conversion rate to AUD for that particular day and that will reflect on your bill.
I was in India last year. I did my normal shopping with my credit card and all transactions were done in Indian Rupees (INR). Bankwest converted INR to AUD for that particular day and that was seen on my iphone app and the bill. Let me tell you what, it was SPOT ON!! Finally, I was happy, shopping was happy and Bankwest was happy!
Hope I have helped you atleast a bit.
Mathews replied on May 11, 2016