It appears to be working now.
It seems customers so far haven't had any problems with it, except international (which i have set to default to a set amount)..
I think it had something to do with that fact my cart contents were stored in a cookie from a previous day.
I cleared my cookies, then tried again with the code that you posted, and it calculated the postage fine.
It didn't give anything for full request and response.. I put that code on the pp_confirm.php page.. (edit... my bad, i had the eCart object name wrong)
I just ran through an order for an international address and here is the response.
Full Requesst: Pickup_Postcode=5046&Destination_Postcode=90211&Country=US&Service_Type=STANDARD&Weight=45&Length=100&Width=100&Height=100&Quantity=1.0
Full Response: charge=0 days=0 err_msg=Standard Postage Rates not available for areas outside Australia