HttpWebRequest problem with WWW-authenticate header

[Proogeren]

I have a problem with a httpwebrequest that I am creating. The request in itself looks correct but using fiddler I see that a www-authentication header is sent along as well. The code is pasted below. I do not add any www-authentication header here so I was wondering if anyone knows how to remove it.
I have used almost 2 days trying to figure this out so help would be highly appreciated.

CORRECT
No proxy-authenticate header is present
no www-authenticate header is present

WRONG
No proxy-authenticate header is present
www-authenticate header is present. Basic realm="Portal Agent"

So my problem is to remove the www-authenticate header

public void WebRequestUploadTes ()
        {
            string url = "http://test/foto/bin/upload.dll";
            string file = @"C:\Untitled.jpg";
            UploadFilesToRemoteUrl(url, file);
        }
 
        private void UploadFilesToRemoteUrl(string url, string file)
        {
            string boundary = "--" + DateTime.Now.Ticks.ToString("x");
 
            // Create the web request
            HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
            httpWebRequest.Method = "POST";
            httpWebRequest.ServicePoint.Expect100Continue = false;
 
            byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("--" + boundary + "\r\n");
 
            string header = "Content-Disposition: form-data; name=\"username\" \r\n\r\ntesuser ";
            header += "\r\n--" + boundary + "\r\n";
            header += "Content-Disposition: form-data; name=\"password\" \r\n\r\n123 ";
            header += "\r\n--" + boundary + "\r\n";
 
            // file upload
            header += "Content-disposition: attachment; name=\"file1\"; filename=\"Oryx Antelope.jpg\"\r\n";
            header += "Content-type: application/octet-stream\r\n";
            header += "Content-Transfer-Encoding: binary\r\n";
 
 
            //convert the header to a byte array
            byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
 
            // Add all of the content up.
            httpWebRequest.ContentLength = new FileInfo(file).Length + headerbytes.Length + (boundarybytes.Length * 2) + 2;
 
            httpWebRequest.ContentType = "multipart/form-data; boundary=" + boundary;
 
            httpWebRequest.Headers["Pragma"] = "no-cache";
 
            // Get the output stream
            Stream requestStream = httpWebRequest.GetRequestStream();
 
            // Write out the starting boundry
            requestStream.Write(boundarybytes, 0, boundarybytes.Length);
 
            // Write the header including the filename.
            requestStream.Write(headerbytes, 0, headerbytes.Length);
            // Open up a filestream.
            FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);
 
            // Use 4096 for the buffer
            byte[] buffer = new byte[4096];
 
            int bytesRead = 0;
            // Loop through whole file uploading parts in a stream.
            while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
            {
                requestStream.Write(buffer, 0, bytesRead);
                requestStream.Flush();
            }
 
            boundarybytes = System.Text.Encoding.ASCII.GetBytes("--" + boundary + "--\r\n");
 
            // Write out the trailing boundry
            requestStream.Write(boundarybytes, 0, boundarybytes.Length);
 
            // Close the request and file stream
            requestStream.Close();
            fileStream.Close();
 
 
            try
            {
                WebResponse webResponse = httpWebRequest.GetResponse();
 
                Stream responseStream = webResponse.GetResponseStream();
                StreamReader responseReader = new StreamReader(responseStream);
 
                string responseString = responseReader.ReadToEnd();
 
                // Close response object.
                webResponse.Close();
 
            }
            catch (Exception)
            { }
        }
 
 
 
 

[Plater]

It would get added in if the server returned a status requiring it (401 unauthorized)
Did you watch the entire series of transactions? I bet somewhere the server made that request?