Provare ad usare questo:

<%
URL = "http://www.sito.com/index.htm"
Set objXmlHttp = Server.CreateObject("MSXML2.ServerXMLHTTP")
objXmlHttp.Open "GET", URL, False
objXmlHttp.send
strHTML = objXmlHttp.responseText
Set xml = Nothing
response.write(strHTML)
%>