I have installed Java Tomcat V5 and all seems to be working of a fashion.
What I need to be able to setup is so that both work from the default webpage
http://servername
You need to be really careful when installing new software on SME because it would be really easy make a mess of things if you aren't careful. SME is a complex set of mechanisms sitting on top of a stripped down Centos. Installing software not in core Centos could quite easily break something in the connection between Centos and the SME mechanisms. I'd read the developers guide on this site before going any further.
While I'm not familar with Tomcat, it appears to me to add functionality to Apache. Usually when you add functionality to Apache, changes need to occur in httpd.conf. Don't modify this file directly as it is generated by configuration templates. Instead, create custom templates or possibly modify existing templates to generate the changes you are after. The standard templates for httpd are located at /etc/e-smith/templates/etc/httpd/conf/httpd. You'll want to override any of these templates or create new onces in /etc/e-smith/templates-custom/etc/httpd/conf/httpd.conf.
Good luck.