First of all, I assume you will need a SSL connector in Tomcat. This is also where you will install the certificate for the web service.
Good instructions are available at: http://tomcat.apache.org/tomcat-6.0-doc/ssl-howto.html Note that the default SSL connector uses port 8443, which you may want to change to port 443.
Second, you also need to configure the web.xml deployment descriptor of the web service like this:
Let me know if the above does not work for you.