Remote testing of web services via HTTP was diabled by default after .Net 1.0, so now you can only invoke test methods with your browser on the server.
Should you ever find the need to enable it again, add the following to the system.Web section of your web.config:
<webServices>
<protocols>
<add name="HttpPost" />
<add name="HttpGet" />
</protocols>
</webServices>
Tom Hundley
Elegant Software Solutions, LLC