Here's an example I found on the web.

Dim oXMLHTTP As MSXML2.XMLHTTP40
Set oXMLHTTP = New MSXML2.XMLHTTP40
oXMLHTTP.open "GET", [your XML returning URL], False
oXMLHTTP.send
msgbox oXMLHTTP.responseXML


So it looks like your "senddata" needs to be a URL.