SignedData (applied by the RA)
        PKIData
          controlSequence (Transaction ID, Sender Nonce,
                                               Batch Requests)
          cmsSequence
            SignedData (applied by client)
              PKIData
                controlSequence (Transaction ID, Sender Nonce)
                reqSequence
                  TaggedRequest
                  {TaggedRequest}
            {SignedData     (second client request)
              PKIData...}