Index: includes/HttpClientXMLFormatter.inc
===================================================================
--- includes/HttpClientXMLFormatter.inc	(revision 2049)
+++ includes/HttpClientXMLFormatter.inc	(revision 2050)
@@ -67,7 +67,7 @@
         }
         else {
           $assoc = TRUE;
-          $key = preg_replace('/[^a-z0-9_]/', '_', $key);
+          $key = preg_replace('/[^A-Za-z0-9_]/', '_', $key);
           $key = preg_replace('/^([0-9]+)/', '_$1', $key);
         }
         $element = $doc->createElement($key);