return null;
}
try {
//Create a retrieval method over the given element
RetrievalMethod rm = new RetrievalMethod(element, BaseURI);
String type = rm.getType();
XMLSignatureInput resource=resolveInput(rm,BaseURI);
if (RetrievalMethod.TYPE_RAWX509.equals(type)) {
//a raw certificate, direct parsing is done!
X509Certificate cert=getRawCertificate(resource);
if (cert != null) {