Node assert2 = DocumentUtil.getNodeWithAttribute(doc, "urn:oasis:names:tc:SAML:2.0:assertion", "Assertion", "ID", id);
String referenceURI = "#" + id;
assertNotNull("Found assertion?", assert2);
SAML2Signature ss = new SAML2Signature();
Document signedDoc = ss.sign(responseType, id, kp, referenceURI);
JAXPValidationUtil.validate(DocumentUtil.getNodeAsStream(signedDoc));
Node signedNode = DocumentUtil.getNodeWithAttribute(signedDoc, "urn:oasis:names:tc:SAML:2.0:assertion", "Assertion",
"ID", id);