UrbanRunr, Thank you for your time in trying to set up your account with our Auto Pay option! The option to enroll with an International Credit Card does depend on the type of billing zip code. Is the Billing zip code is all numberic (99999)? If it is Alpha-Numeric (P88K22); the APO option would have to be set up using our phone Automated System. The number to enroll using this service is 866-868-3882. Please let us know if you have further questions.