Just a side note -

I got confirmation that the USPS International Priority Shipping option works fine in GCO. I got an order in my zen-cart for 2 books. The customer info was there, the shipping address was all there, the quantities were properly decremented, and the status was Pending. All was as it should be!

The kicker was that I had to go to Google site to find out that the payment had been denied as the credit card was not accepted. I cancelled the order through the Google interface.