Invoking a Web Service behind the firewall

hi,
I am trying to invoke a web service outside the firewall using the webMethods Web Service connector.
webMethods Integration Server is behind the firewall and to invoke the web service(outside the firewall) where and how I should pass the proxy server authentication details ?

Thanks
Fass

Fass - you need to configure the outbound proxy setting in the IS administrator. Click the Proxy link under Settings.