Those version of JBoss and Tomcat are not supported by Red Hat.
You may get trouble upgrading for TC-5.0.26 to TC-5.5.26.
The TC-5.0.x we "support" in RHEL package is TC-5.0.30 (5.0.30.patch03-brew).
I'm basically in the same situation relative to having to update Tomcat.
What I'm curious about is whether I can update Tomcat independently of JBoss. Is a particular version of JBoss tied to a particular version of Tomcat? Is is possible to copy the updated version of jar files to the server?
Also, I can't find a source that lists what version Tomcat a particular version of JBoss includes. Any ideas where I can find this information?