Unmarshaller unmarshaller = null;
Set<Element> referenceParameterHeaders = null;
QName invalidCardinalityQName = null;
Iterator<Header> iter = header.iterator();
while (iter.hasNext()) {
Header hdr = iter.next();
if (hdr.getObject() instanceof Element) {
Element headerElement = (Element)hdr.getObject();
String headerURI = headerElement.getNamespaceURI();
// Need to check the uri before getting unmarshaller else
// would get wrong unmarshaller and fail to process required
// headers.
if (VersionTransformer.isSupported(headerURI)) {