In short, you cannot run a web service from Base SAS. The SAS supported approach to a web service is the "SAS Information Delivery Portal" or the "SAS Web Report Studio". You can look at the technical specs at support.sas.com to see what you need to do for them. Even they require a separate web tool to establish the basic connectivity and services.
Another alternative is to use SAS to generate a host of reports on a periodic basis (daily, monthly, etc) and store them on the web for a regular web server to host.
Another alternative is to have the web tool collect the parameters (macro values, say) and submit the code to the SAS server for execution and placement of the report.