It looks like you have a namespace-aware DOM. The docs say you need to provide the Qualified Name Representation of the element:
private static String qualifiedNameRepresentation(Element e) {
String ns = e.getNamespaceURI();
String local = e.getLocalName();
return (ns == null) ? local : '{' + ns + '}' + local;
}
So the value of the property will be of the form {http://your.conn.namespace}setting
.