I am in the process of building the webapp now, so I should have an answer in a few days. However, this is a better question for either the Tomcat users group (jakarta.apache.org) or the apache user list (www.apache.org). Have you tried submitting your questions there, or viewing the Tomcat user archives?
Sorry, all. Took Randy's advice and looked at the tomcad-user list archive. All I had to do to fix it was uncomment the general ServerName directive in my httpd.conf. Seems that mod_webapp cares about this whereas mod_jk didn't. localhost is fine, of course. Thanks, Randy.