we had a requirement where we had to call webservices from a btm biztalk map.
the script functoid called an external assembly which in turn called a 3rd party webservice on the internet.
this required a proxy server since it is on the internet.
this is how we solved it by configuring the btsntsvc.exe.config.
Pls restart the Application and host after the change.
<add address="*" maxconnection="40"/>
<proxy usesystemdefault="true" bypassonlocal="true" proxyaddress="http://x.x.x.x:80" />
<add address="172.22.*.*" />
<add address="localhost" />