Ksoap sending request in null

I have the following code using the Ksoap2-android-3.6.0 library

@Override
    protected Void doInBackground(String... params) {
        try {

            SoapObject request = new SoapObject(NAME_SPACE, METHOD);
            PropertyInfo propertyAutentica = new PropertyInfo();

            Autentica autenticacion = new Autentica();
            autenticacion.setLogin("mi clave");
            autenticacion.setPassword("mi password");

            propertyAutentica.setName("Autenticacion");
            propertyAutentica.setValue(autenticacion);
            propertyAutentica.setType(Autentica .class);

            request.addPropertyIfValue(propertyAutentica);

            // Modelo el Sobre
            SoapSerializationEnvelope envp = new SoapSerializationEnvelope(SoapEnvelope.VER11);
            envp.dotNet = true;
            envp.implicitTypes = false;

            envp.setOutputSoapObject(request);

            // Modelo el transporte
            HttpTransportSE transporte = new HttpTransportSE(url,30000);
            transporte.debug = true;

            Log.d("Resultado", "request :: "+transporte.requestDump);

            // Llamada
            transporte.getServiceConnection().connect();
            transporte.call(accionSoap, envp);



            // Resultado
            SoapObject resultado = (SoapObject) envp.getResponse();

            Log.d("Resultado", resultado.toString());

        } catch (XmlPullParserException e) {
            Log.d("Resultado", e.toString());
        } catch (HttpResponseException e) {
            Log.d("Resultado", e.toString());
        } catch (SoapFault soapFault) {
            Log.d("Resultado", soapFault.toString());
        } catch (IOException e) {
            Log.d("Resultado", e.toString());
        }
        return null;
    }

Authentication Class

public class ItemAutenticacion implements KvmSerializable {

    private String Login;
    private String Password;

    public String getLogin() {
        return Login;
    }

    public void setLogin(String login) {
        Login = login;
    }

    public String getPassword() {
        return Password;
    }

    public void setPassword(String password) {
        Password = password;
    }


    @Override
    public Object getProperty(int i) {
        switch(i)
        {
            case 0:
                return Login;
            case 1:
                return Password;
        }

        return null;
    }

    @Override
    public int getPropertyCount() {
        return 2;
    }

    @Override
    public void getPropertyInfo(int i, Hashtable hashtable, PropertyInfo propertyInfo) {
        switch(i)
        {
            case 0:
                propertyInfo.type = PropertyInfo.STRING_CLASS;
                propertyInfo.name = "Login";
                break;
            case 1:
                propertyInfo.type = PropertyInfo.STRING_CLASS;
                propertyInfo.name = "Password";
                break;
        }
    }

    @Override
    public void setProperty(int i, Object o) {
        switch (i){
            case 0:
                Login = o.toString();
                break;
            case 1:
                Password = o.toString();
                break;
        }
    }
}

The web service is made in Visual Basic and the problem I have is that my type authenticates me as null or Nothing and the log of

  

Log.d ("Result", "request ::" + transport.requestDump);

Returns to me

  

D / Result: request :: null

What do I need to add to send the data in the request?