Oh, sorry about that, I assumed that you were already working with these bindings. These values are located in the bindings tab under the usps result. Here they are for reference:
<?php echo $_SESSION["WA_Store_Cart_USPS_FullRequest"]; ?>
<?php echo $_SESSION["WA_Store_Cart_USPS_FullResponse"]; ?>
You would want to put these on the shipping failure page and any other page after the confirm page that you would like to see these values.