Add hook_alter for catching and debugging the requests and responses.

Proposed patch:

--- a/uc_salesforce/uc_sf_order/uc_sf_order.module
+++ b/uc_salesforce/uc_sf_order/uc_sf_order.module
@@ -635,6 +635,7 @@ function uc_sf_order_export($order, $name, $sfid = NULL, $manual = FALSE) {
     // Export the object to Salesforce.
     try {
       $response = $sf->client->create(array($object), $map->salesforce);
+      drupal_alter('uc_sf_order', $response, $sf);
     }
     catch (Exception $e) {
       drupal_set_message(t('Error exporting order to Salesforce.'), 'error');
@@ -681,6 +682,7 @@ function uc_sf_order_export($order, $name, $sfid = NULL, $manual = FALSE) {
         }
         try {
           $product_responses = $sf->client->create($product_objects, $uc_order_products_fieldmap->salesforce);
+          drupal_alter('uc_sf_order', $product_responses, $sf);
         }
         catch (Exception $e) {
           sf_dpm($e->faultstring, 'Ubercart order line item exception');
@@ -718,6 +720,7 @@ function uc_sf_order_export($order, $name, $sfid = NULL, $manual = FALSE) {
       else {
         $user_object_export = salesforce_api_fieldmap_export_create($user_map_id, $account);
         $user_response = $sf->client->create(array($user_object_export), $user_map->salesforce);
+        drupal_alter('uc_sf_order', $user_response, $sf);
         $account_sfid = $user_response->id;
       }
     }

Example usage:

/**
 * Implements hook_TYPE_alter().
 */
function foo_uc_sf_order_alter($response, $sf) {
  $xml_request = $sf->client->getLastRequest();
  $xml_response = $sf->client->getLastResponse();
} 

See also:
http://drupal.stackexchange.com/questions/89812/how-to-debug-queries-and...