MESSAGE sip:colab@acme.pt SIP/2.0
      Via: SIP/2.0/UDP 127.0.0.1:5555;rport;branch=[branch]
      To: <sip:colab@acme.pt>
      From: "Gestor" <sip:gestor@acme.pt>;tag=[call_number]
      Call-ID: [call_id]
      CSeq: 1 MESSAGE
      Max-Forwards: 70
      Content-Length: [len]
      Content-Type: text/plain;charset=utf-8

      ADD <sip:colaboradorBob@acme.pt>