diff --git a/outputxml.php b/outputxml.php
index 6b1ff61..4c37b35 100644
--- a/outputxml.php
+++ b/outputxml.php
@@ -28,7 +28,7 @@ class outputxml extends output
       {
         $key = is_numeric($key) ? "item$key" : $key;
         $subnode = $xml->addChild("$key");
-        array_to_xml($value, $subnode);
+        $this->array_to_xml($value, $subnode);
       }
       else
       {