Logging in to HTTPS interface of Serv-U server

Question

I am trying to connect to a corporate ftp server via code (C#/VB). It has been set up to run in a browser using SolarWinds Serv-U software so that users can access it via a browser. The address is in the form:

https://ftp.example.com

From here they are presented with a login form (part of Serv-U) in which they enter their u/p and log in.

I have been trying to use HttpWebRequest class to log in, but each time I get an '401 Unauthorised - not logged in' error. In the web request I set the credentials:

Dim loginUri = New Uri("https://ftp.example.com")
Dim loginRequest As HttpWebRequest = DirectCast(WebRequest.Create(loginUri), HttpWebRequest)

    With loginRequest

        .Accept = "*/*"
        .ContentType = "application/x-www-form-urlencoded"
        .CookieContainer = New CookieContainer()
        .Credentials = New NetworkCredential("user", "pass")
        .Method = WebRequestMethods.Http.Get

    End With

Dim loginResponse As HttpWebResponse = loginRequest.GetResponse()

I'm not even sure if this approach is possible; there are quite a number of cookies set by the browser during the login process which is not a desirable thing to replicate in code.

I've done a fair bit of searching on the subject and haven't found any definitive answers. Should I just push back on the sysadmin to set up a proper ftp server over SSL? It is a requirement that we use :443 as many firewalls block 21 (& 22).

Thanks - Z