I just had to do this exact same thing. I used MS Access as my tool. But you could use VB or even Excel (or as someone will tell you c++, c#, etc, etc) But this example is for VB/VBA based products.
Here is the code I wrote:
You have to add the following reference (hopefully you know how to do this already
Microsoft WinHTTP Services
Public Sub Test()
Dim webReq As New WinHttpRequest
Dim strResponse as String
Dim strXML as String
webReq.Open "POST", "https://URL_TO_POST_TO"
strXML = "<?xml version='1.0' encoding = 'UTF-8'?>" _
& vbCrLf & "<YOUR_XML>" _
& vbCrLf & " <Session>" _
& vbCrLf & " </Session>" _
& vbCrLf & " <Request>" _
& vbCrLf & " <Name>" _
& vbCrLf & " </Name>" _
& vbCrLf & " </Request>" _
& vbCrLf & "</YOUR_XML>"
webReq.Send strXML
webReq.WaitForResponse
strResponse = webReq.ResponseText
debug.print strResponse
End Sub
You could also read the XML file into the strXML variable if you wanted.
Hope this helps
Craig