Авторизация через HttpWebRequest - В возвращённом HTML-файле пользователь всё ещё не залогинен

private void PostData(string url)
        {
            string boundary = "--------------------------" + DateTime.Now.Ticks.ToString();
 
            HttpWebRequest getRequest = (HttpWebRequest)WebRequest.Create(url);
            getRequest.CookieContainer = new CookieContainer();
            getRequest.CookieContainer.Add(cookies);
            getRequest.KeepAlive = true;
            getRequest.Method = WebRequestMethods.Http.Post;
            getRequest.UserAgent = "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/15.0.874.121 Safari/535.2";
            getRequest.ProtocolVersion = HttpVersion.Version11;
            getRequest.AllowAutoRedirect = true;
            getRequest.ContentType = "multipart/form-data; boundary=" + boundary;
            Stream newStream = getRequest.GetRequestStream();
 
            byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
 
            fdc.WriteDataToStream(newStream, boundarybytes);
 
            newStream.Close();
            HttpWebResponse getResponse = (HttpWebResponse)getRequest.GetResponse();
            cookies = getResponse.Cookies;
            using (StreamReader sr = new StreamReader(getResponse.GetResponseStream()))
            {
                lastResponse = sr.ReadToEnd();
            }
            fdc.Clear();
}

public void WriteDataToStream(Stream stream, byte[] boundarybytes)
        {
            string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
            foreach (string key in FormData.AllKeys)
            {
                stream.Write(boundarybytes, 0, boundarybytes.Length);
                byte[] itembytes = System.Text.Encoding.UTF8.GetBytes(String.Format(formdataTemplate, key, FormData.Get(key)));
                stream.Write(itembytes, 0, itembytes.Length);
            }
            stream.Write(boundarybytes, 0, boundarybytes.Length);
        }

private void PostDataSimple(string url, string login, string password)
        {
            HttpWebRequest getRequest = (HttpWebRequest)WebRequest.Create(url);
            getRequest.CookieContainer = new CookieContainer();
            getRequest.CookieContainer.Add(cookies);
            byte[] dataStream = Encoding.UTF8.GetBytes(String.Format("login[email]={0}&login[password]={1}", login, password));
            getRequest.Method = WebRequestMethods.Http.Post;
            getRequest.ContentType = "application/x-www-form-urlencoded";
            getRequest.UserAgent = "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/15.0.874.121 Safari/535.2";
            getRequest.UseDefaultCredentials = true;
            getRequest.ProtocolVersion = HttpVersion.Version11;
            getRequest.AllowAutoRedirect = true;
            getRequest.ContentLength = dataStream.Length;
 
            Stream newStream = getRequest.GetRequestStream();
            newStream.Write(dataStream, 0, dataStream.Length);
            newStream.Close();
            HttpWebResponse response = (HttpWebResponse)getRequest.GetResponse();
            cookies = response.Cookies;
            using (StreamReader sr = new StreamReader(response.GetResponseStream()))
            {
                lastResponse = sr.ReadToEnd();
            }
        }

private void _BugFix_CookieDomain(CookieContainer cookieContainer)
        {
            System.Collections.Hashtable table = (System.Collections.Hashtable)cookieContainer.GetType().InvokeMember("m_domainTable",
                System.Reflection.BindingFlags.NonPublic |
                System.Reflection.BindingFlags.GetField |
                System.Reflection.BindingFlags.Instance,
                null,
                cookieContainer,
                new object[] { }
            );
            System.Collections.ArrayList keys = new System.Collections.ArrayList(table.Keys);
            foreach (string keyObj in keys)
            {
                string key = (keyObj as string);
                if (key[0] == '.')
                {
                    string newKey = key.Remove(0, 1);
                    table[newKey] = table[keyObj];
                }
            }
        }