With the classic AppServer ( pre-Pacific AppServer ):
The WSA is a Java servlet. You need a Java Servlet Engine like Tomcat to host it. You then need to configure your web server ( IIS in your case ) to redirect request to Tomcat.
Whith Pacific AppServer Tomcat comes packaged with OpenEdge. Still you need to configure your web server to redirect the request to Tomcat.
Heavy Regards, RealHeavyDude.