>>354
>imageField.x 65
>imageField.y 20

ieHTTPheadersでログインを見てみたら、x=73、y=17でした。
動的に変わるのかな？

あと、data作ったあとはこんな感じです

　　CookieContainer cc = new CookieContainer();
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
req.ContentLength = data.Length;
req.CookieContainer = cc;

Stream reqStream = req.GetRequestStream();
reqStream.Write(data, 0, data.Length);
reqStream.Close();

WebResponse res = req.GetResponse();
Stream resStream = res.GetResponseStream();

Encoding encoder = Encoding.GetEncoding("SJIS");
StreamReader sr = new StreamReader(resStream, encoder);
string result = sr.ReadToEnd();
sr.Close();
resStream.Close();