Dim request As Net.FtpWebRequest = Net.FtpWebRequest.Create( _
  "ftp://meinserver.de/unterordner1/unterordner2/unterordner3/")
request.Method = Net.WebRequestMethods.Ftp.ListDirectory
request.Credentials = New Net.NetworkCredential("acc", "pw")
Dim response As Net.FtpWebResponse = request.GetResponse()
Using myReader As New IO.StreamReader(response.GetResponseStream())
Do While myReader.EndOfStream = False
list_Files_01.Items.Add(myReader.ReadLine())
Loop
End Using