code: public EnrollmentResponse enrol(final X509Certificate identity,
              final PrivateKey key, final PKCS10CertificationRequest csr)
              throws ClientException, TransactionException {
          return enrol(identity, key, csr, null);
      }
docs: Sends a CSR to the SCEP server for enrolling in a PKI.
  <p>
  This method enrols the provider <tt>CertificationRequest</tt> into the
  PKI represented by the SCEP server.
  
  @param identity
  the identity of the client.
  @param key
  the private key to sign the SCEP request.
  @param csr
  the CSR to enrol.
  @return the certificate store returned by the server.
  @throws ClientException
  if any client error occurs.
  @throws TransactionException
  if there is a problem with the SCEP transaction.
  @see CertStoreInspector