Problemas com subject alternative name em CSR

olá,

estou com problemas para adicionar um subject alternative name especifico (CNPJ) ao CSR,

estou utilizando a api bouncycastle para gerar o CSR,

vejam:

	public static PKCS10CertificationRequest generateRequestCNPJ(KeyPair pair) throws Exception
	{
		DERObjectIdentifier oidCnpj = new DERObjectIdentifier("2.16.76.1.3.3");

		Vector oid = new Vector();
		Vector value = new Vector();

		oid.add(oidCnpj);
		value.add("12345678909");
		ASN1Encodable nm = new X509Name(oid, value);

		GeneralNames san = new GeneralNames(new GeneralName(GeneralName.otherName, nm));

		Vector oids = new Vector();
		Vector values = new Vector();

		oids.add(X509Extensions.SubjectAlternativeName);
	
		values.add(new X509Extension(false, new DEROctetString(san)));
	
		X509Extensions extensions = new X509Extensions(oids, values);

		Attribute attribute = new Attribute(PKCSObjectIdentifiers.pkcs_9_at_extensionRequest, new DERSet(extensions));

		return new PKCS10CertificationRequest("SHA256withRSA", new X500Principal("CN=Requested Test Certificate"), pair.getPublic(), new DERSet(attribute), pair.getPrivate());
	}

onde estou errando no código?