I noticed that you have not received any feedback on this so I thought I would try to add something. I do not think you will be able to make use of Authorize.net outside of the US but Payments Pro should still work for you. You would need to obtain a US Business account with PayPal in order to sign up for Payments Pro US though. I'm not sure if this is an option for you but I think it would be possible to use this one.