public static string GetHtmlSource(string siteUrl, ICredentials credentials, CookieContainer cc)
{
    string resourceUrl = siteUrl;
    HttpWebRequest wreq = HttpWebRequest.Create(resourceUrl) as HttpWebRequest;
    wreq.Credentials = credentials;
    wreq.CookieContainer = cc;
    wreq.Method = "POST";
    wreq.UserAgent = HtmlControlConstants.USERAGENT;
    wreq.ContentLength = 0;
    wreq.ContentType = HtmlControlConstants.CONTENTTYPE;
    string result;
    WebResponse wresp = wreq.GetResponse();
    using (StreamReader sr = new StreamReader(wresp.GetResponseStream()))
    {
        result = sr.ReadToEnd();
    }
    return result;
}