private void btnSolicitar_Click(object sender, EventArgs e)
        {
            if (String.IsNullOrEmpty(txtDestinoTexto.Text))
            {
                MessageBox.Show("Informe o e-mail de destino da solicitação de assinatura", "ERRO", MessageBoxButtons.OK);
                return;
            }

            var req = new SignatureSimpleDocumentReqType()
            {
                TestMode = true,
                DataToBeSigned = txtAssinarTexto.Text,
                MobileUser = new MobileUserType() { UniqueIdentifier = txtDestinoTexto.Text },
                MessagingMode = MessagingModeType.asynchClientServer
            };

            SignatureService service = new SignatureService();

            var resp = service.SignatureSimpleDocument(req);

            txtLogTexto.Text = string.Format("Servidor retornou {0}\r\n", resp.Status.StatusMessage);
            txtTransacaoTexto.Text = resp.TransactionId.ToString();
        }