HttpWebRequest Credintial fejler

Hej Eksperter
jeg forsøger at få adgang til WorlPays modul. Spørgmålet her er det samme som jeg laver:
http://forums.asp.net/p/1501279/3553954.aspx

Her findes andre programmeringssprog som laver det jeg skal kunne lave:
http://support.worldpay.com/support/gg/index.php?page=examples&amp%3bc=WW

I den anden ende får jeg Authentication Errors
[2016-08-17 09:19:20.267 (TID:a7c92d697cc3ec4b)] {INFO/XMLAuthFilter}: Authentication Failure : { ipAddress=XX.YY.z.14, userName="null", reason="No Auth Header" }



Mine Credintials fejler og jeg har forsøgt mig med mange muligherder.Blandt andet Credential 1 + 2 + 3, som I kan se her er udkommenteret:


  public string XML2Bibitversion2(string sXML, string sURL, string sUser, string sPass)
    {
      HttpWebRequest request = null;
      HttpWebResponse response = null;
      byte[] bytes;
      // sURL:

      XDocument document = new XDocument();
      try
      {
        // bytes = Encoding.ASCII.GetBytes("" +sXML +"," +sUser+","+sPass);
        bytes = Encoding.ASCII.GetBytes(sXML);
        request = (HttpWebRequest)WebRequest.Create(sURL);
        request.PreAuthenticate = true;

        // Credential 1
        /*
        CredentialCache mycache = new CredentialCache();
        mycache.Add(new Uri(sURL), "Digest", new NetworkCredential(sUser, sPass));
        request.Credentials = mycache;
        */

        // Credential 2) Building my own Header
        /*
        string credentials = Convert.ToBase64String(ASCIIEncoding.ASCII.GetBytes(sUser + ":" + sPass));
        request.Headers.Add("Authorization", "Basic " + credentials);
        */


        // Credential 3) Building my own Header
        /*
        string credentials = String.Format("{0}:{1}", sUser, sPass);
        byte[] credbytes = Encoding.ASCII.GetBytes(credentials);
        string base64 = Convert.ToBase64String(credbytes);
        string authorization = String.Concat("Basic ", base64);
        request.Headers.Add("Authorization", authorization);
        */


        request.ContentType = "text/xml; encoding='utf-8'";
        request.ContentLength = bytes.Length;
        request.Method = "POST";
        Stream requestStream = request.GetRequestStream();
        requestStream.Write(bytes, 0, bytes.Length);
        requestStream.Close();
        Thread.Sleep(2000);
        using (response = (HttpWebResponse)request.GetResponse())
        {
          if (response.StatusCode == HttpStatusCode.OK)
          {
            Stream responseStream = response.GetResponseStream();
            string responseStr = new StreamReader(responseStream).ReadToEnd();
            return responseStr;
          }
          return null;
        }
      }
      catch (Exception ex)
      {
        return ex.ToString();
      }
    }