const string uri = "https://darkorbit.com/login/index.php";
    HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(uri);
    wr.KeepAlive = true;
    wr.Method = "POST";
    wr.AllowAutoRedirect = false;
    wr.Proxy = p;
    wr.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
    wr.ContentType = "application/x-www-form-urlencoded";
    wr.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.111 Safari/537.36";
    string pdata = "username=USERNAME&password=PASSWORD";
    byte[] data = UTF8Encoding.UTF8.GetBytes(pdata);
    wr.ContentLength = data.Length;
    CookieContainer cookie = new CookieContainer();
    wr.CookieContainer = cookie;
    using (Stream poststream = wr.GetRequestStream())
    {
        poststream.Write(data, 0, data.Length);
    }
    HttpWebResponse wp = (HttpWebResponse)wr.GetResponse();
    wr.CookieContainer.Add(wp.Cookies);