Download file da sito tramite https e parametri

            url = "https://....?param1=***&param2=***...."
            Dim wr As HttpWebRequest = CType(WebRequest.Create(url), HttpWebRequest)
      wr.Credentials = New NetworkCredential(mioUtente, miaPassword)
            Dim ws As HttpWebResponse = CType(wr.GetResponse(), HttpWebResponse)

            Dim str As Stream = ws.GetResponseStream()

            Dim inBuf(100000) As Byte
            Dim bytesToRead As Integer = CInt(inBuf.Length)
            Dim bytesRead As Integer = 0
            While bytesToRead > 0
                Dim n As Integer = str.Read(inBuf, bytesRead, bytesToRead)
                If n = 0 Then
                    Exit While
                End If
                bytesRead += n
                bytesToRead -= n
            End While
            Dim fstr As New FileStream(nomefile & ".txt", FileMode.OpenOrCreate, FileAccess.Write)
            fstr.Write(inBuf, 0, bytesRead)
            str.Close()
            fstr.Close()