That looks more like it. So just put that http post stuff into the vba, something like below. You will have to finish it off yourself
To get stuff to appear formatted nicely on this forum you gotta put code tags around it. This means code and /code in square brackets.
Disclaimer: Not my area of expertise.
Dim WinHttpReq As Object
Set WinHttpReq = CreateObject("WinHttp.WinHttpRequest.5.1")
Dim strURL As String
Dim StrFileName As String
Dim FormFields As String
strURL = "http://put.your.url.here/"
WinHttpReq.Open "POST", strURL, False
' Set the header
WinHttpReq.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
FormFields = "_blank" ' this bit comes from the http post target bit I think
' Display the status code and response headers.
' The response should contain the file!!! So save this to disk.
SomeBinaryObject.save() ' i totally made this bit up