WebClient.DownloadData to access a pdf in unfriendly domain with windows auth - credentials do not work

I am trying to download a pdf in my dmz, and my credentials for that domain do not seem to work. I think it is because I am using Windows Authentication, which I must use.

I have even tried creating my own headers to no avail.

Dim auth AsString = String.Format(_username& ":"& _pwd)

Dim enc AsString = Convert.ToBase64String(Encoding.ASCII.GetBytes(auth))

Dim cred AsString = String.Format("NTLM"& enc)

client.Headers.Add(HttpRequestHeader.Authorization, cred)

Sorry. Duplicate ... sorta to this ... http://forums.asp.net/t/1981833.aspx?Accessing+a+PDF+from+intranet+through+firewall+in+DMZ+using+WebClient+DownloadData