the .net interop type cannot be used in code for the classic

Hello,

I had made a DLL in C#, easy, and put them under "C:\Program Files (x86)\Microsoft Dynamics NAV\60\Service\Add-ins".

The problem is :

1) I had declared a global variable DotNet of my DLL
2) I had Implemented the global variable
3) I had compiled my codeunit without error

but when I ran my codeunit, those got me this error : the .net interop type cannot be used in code for the classic.

C/AL code in form

sgatePXY := sgatePXY.SGATEProxy;

this is my DLL

using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Xml;

namespace ClassLibrarySGATE
{
public class SGATEProxy
{
public X509Certificate certified;
public SgateWebService ProxySgate;

protected string Pass;
protected string User;
public tipoRispostaPresaInCaricoLotto result;
public tipoRichiestaPresaInCaricoLotto request;
public string requestXML;
public XmlDataDocument XDom;
public XmlNodeList xNodeList;
protected string idUltimoLottoRicevutoCorrettamente;
protected string NumeroMessaggi;


public SGATEProxy()
{
}

public bool CallSgateServer(string pathCertificati, string url, string username, string password)
{
ProxySgate = new SgateWebService();
XDom = new XmlDataDocument();
// Invio i certificati tramite il collegamento proxy web senza doverli registrare sul pc o server
ProxySgate.ClientCertificates.Add(X509Certificate.CreateFromCertFile(pathCertificati + "SGATE.cer"));
ProxySgate.ClientCertificates.Add(X509Certificate.CreateFromCertFile(pathCertificati + "GeoTrustPCA.cer"));
ProxySgate.ClientCertificates.Add(X509Certificate.CreateFromCertFile(pathCertificati + "GeoTrustEV.cer"));
ProxySgate.ClientCertificates.Add(new X509Certificate(pathCertificati + username, password));
ProxySgate.Timeout = 360 * 1000;
return false;
}

public tipoRispostaPresaInCaricoLotto InvokePresaInCaricoLotto(tipoRichiestaPresaInCaricoLotto request, int tentativo)
{
result = null;
try
{
result = ProxySgate.PresaInCaricoLotto(request);
}
catch
{
if (tentativo < 5)
result = InvokePresaInCaricoLotto(request, tentativo + 1);
}
return result;
}

public string EsitoRichiestaLotto(tipoRichiestaPresaInCaricoLotto rispostaLotto)
{
if (string.IsNullOrEmpty(result.lottoMessaggi.idLotto))
return result.lottoMessaggi.idLotto;
else
return "KO";
}

public tipoRichiestaPresaInCaricoLotto GeneraRequestRichiestaLotto(string requestXML)
{

// Reding the request in XML format
XDom.Load(requestXML);

XmlNode xNodeMittente = XDom.SelectSingleNode("/Mittente");
foreach (XmlNode xNode in xNodeMittente)
{
User = xNode["login"].InnerText;
Pass = xNode["Password"].InnerText;
}
XmlNode xNodeRichiestaPresaInCaricoLotto = XDom.SelectSingleNode("/richiestaPresaInCaricoLotto");
foreach (XmlNode xNode in xNodeMittente)
{
idUltimoLottoRicevutoCorrettamente = xNode["idUltimoLottoRicevutoCorrettamente"].InnerText;
NumeroMessaggi = xNode["numeroMessaggi"].InnerText;
}

request = new tipoRichiestaPresaInCaricoLotto();
request.idUltimoLottoRicevutoCorrettamente = idUltimoLottoRicevutoCorrettamente;
request.mittente = new tipoMittente() { login = User, password = Pass };
request.numeroMessaggi = Convert.ToInt32(NumeroMessaggi);

return request;
}


}
}