Index: typo3/classes/class.typo3ajax.php
===================================================================
--- typo3/classes/class.typo3ajax.php	(revision 4016)
+++ typo3/classes/class.typo3ajax.php	(working copy)
@@ -231,7 +231,15 @@
 	protected function renderAsXML() {
 		header('Content-type: text/xml; charset='.$this->charset);
 		header('X-JSON: true');
-		echo implode('', $this->content);
+		$xmlString = implode('', $this->content);
+			// Use SimpleXML utility to check XML validity
+		if (simplexml_load_string($xmlString)) {
+				// String is valid XML, return it as is
+			echo $xmlString;
+		}
+		else {
+			echo t3lib_div::array2xml($this->content);
+		}
 	}