我有 XML 文檔：    <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">    <soapenv:Header/>    <soapenv:Body>        <saml2p:ArtifactResolve xmlns:saml2p="urn:oasis:names:tc:SAML:2.0:protocol" Version="2.0"                                IssueInstant="2020-06-01T10:25:15+02:00">            <saml2:Issuer xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion">TEST</saml2:Issuer>            <saml2p:Artifact>AAQAAKFbFR94fxqmioAqjJUwfHTFVHTDBTVHdBwwTW+ehcM19zsk=</saml2p:Artifact>        </saml2p:ArtifactResolve>    </soapenv:Body></soapenv:Envelope>我嘗試以這種方式執(zhí)行此操作：$results = array();$filename = 'cert.p12';$password = 'certpass';$priv_key = openssl_pkcs12_read(file_get_contents($filename), $results, $password);$doc = new DOMDocument();$doc->loadXML($xml);$xp = new DOMXPath($doc);$xp->registerNamespace('soapenv', 'http://schemas.xmlsoap.org/soap/envelope/');$xp->registerNamespace('saml2p','urn:oasis:names:tc:SAML:2.0:protocol');$xp->registerNamespace('saml2','urn:oasis:names:tc:SAML:2.0:assertion');$xp->registerNamespace('ds',XMLSecurityDSig::XMLDSIGNS);$artifactResolveNode = $xp->query('/*[local-name()=\'Envelope\']/*[local-name()=\'Body\']/*[local-name()=\'ArtifactResolve\']')->item(0);if($artifactResolveNode){    $objDSig = new XMLSecurityDSig();    $objDSig->setCanonicalMethod(XMLSecurityDSig::EXC_C14N);    $objDSig->addReference(        $artifactResolveNode,        XMLSecurityDSig::SHA256,        array('http://www.w3.org/2000/09/xmldsig#enveloped-signature', 'http://www.w3.org/2001/10/xml-exc-c14n#'),        array('force_uri' => true)    );    $objKey = new XMLSecurityKey(XMLSecurityKey::RSA_SHA256, array('type' => 'private'));    $objKey->loadKey($results['pkey'], FALSE);    $objDSig->sign($objKey);    $objDSig->add509Cert($results['cert']);    $objDSig->appendSignature($doc->documentElement());    echo $doc->saveXML();}我想將 Signature 節(jié)點放在 ISSUER 和 ARTIFACT 之間。此位置對于正確發(fā)送 SOAP 信封非常重要。有可能的？