There is a 2nd edition of this post: Standalone Tomcat with jBoss (2nd Edition)!
This tutorial desribes, how to install and configure a standalone Tomcat, so that a deployed webapp can authenticate against LDAP and connect to a jBoss passing the credentials in every call of an EJB via remote interface , so that the business application can authenticate against the same LDAP, too. The configuration of the jBoss seems to be a more common and better documented task and will be covered in another tutorial, which I will link here later, as soon as I have written it.
WARNING: Please don’t use this solution in a productive system, but for testing purpose only. The custom LdapExtLoginModule presented here exposes the credentials of all online users to all classes using the same class loader! I will add a blog post, as I find a solution for production systems.