Vista - script to POST and open reponse in new window

I am trying to go from a .vbs file that is a working http POST to server, to
opening a broswer window displaying the return URL. I cannot have the script
in a web page, needs to be a stand-alone file executed, and must be pure
vbscript.

A snippet:

Dim objHttp
Set objHttp= Createobject("MSXML2.ServerXMLHTTP")
objHttp.Open "POST",srvr,false
objHttp.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
objHttp.send info

if objHttp.status = 200 then
Dim ws
Set ws = CreateObject("WScript.Shell")
ws.Exec("c:\Program Files\Internet Explorer\iexplore.exe about:Blank")
end if

I also need to ensure I only submit once. Obviously this does not even
attempt it but my baseline to work with. I've tried working with the
argument for iexplore on what is passed in to no avail so far.

Any thoughts or help would be greatly appreciated.