How to post XML data to Secured ( SSL ) Website using Using HttpWebRequest

Hi,

I am using HttpWebRequest to post XML data to SSL URL.

I am using .NET 4.0 and tried many things but nothing worked for me.

1. I have tried adding Cert using in request but it also fails. X509Certificate Cert

try
        {

            ServicePointManager.ServerCertificateValidationCallback += new System.Net.Security.RemoteCertificateValidationCallback(ValidateServerCertificate);

            ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;

            X509Certificate Cert =  null

            #region Certificates
           string issuerName = "My CA";  

            X509Store store = new X509Store(StoreName.Root);
            store.Open(OpenFlags.MaxAllowed);
            X509CertificateCollection col =
              (X509CertificateCollection)store.Certificates.Find(X509FindType.FindByIssuerName, issuerName, true);

            Cert = col[0];

            #endregion        
          
            string RequestString = clsReq.GetModifiedXML();                                             
              
                      

            string URL = @"https://url/abc";
            HttpWebRequest salesRequest = (HttpWebRequest)WebRequest.Create(URL);

            // Adding Certificate in request....
            salesRequest.ClientCertificates.Add(Cert);
            salesRequest.KeepAlive = false;

          
            salesRequest.Credentials = CredentialCache.DefaultCredentials;


            salesRequest.Method = "POST";
            //salesRequest.ContentType = "application/x-www-form-urlencoded";
           // salesRequest.ContentType = "text/html";
           salesRequest.ContentType = "text/xml";

            StreamWriter postdatastream = new StreamWriter(salesRequest.GetRequestStream());
                    
            postdatastream.WriteLine(RequestString);
            postdatastream.Close();
                                
            HttpWebResponse salesResponse = (HttpWebResponse)salesRequest.GetResponse();

            if (salesResponse.StatusCode == HttpStatusCode.OK)
            {
                StreamReader streader = new StreamReader(salesResponse.GetResponseStream());
                string result = streader.ReadToEnd();
                streader.Close();

                Response.Write(result);         


            }
           
            salesResponse.Close();

        }
        catch (Exception ex)
        {
           
        }