If you still haven't gotten yourself to working with JBI, James Lorenzen's blog post walks you through the process in a few simple steps.
So what is the JavaEE Service Engine? It's a highly useful JBI component providing a bridge between the web container (glassfish) and the JBI container (OpenESB), or more specifically the NMR (Normalized Message Router). It's useful because it allows EJBs and Servlets, packaged as web services, to communicate directly with JBI components and vic versa. Consequently, this increases performance since the request/response doesn't have to travel in and out of the HTTP BC and the glassfish Servlet container.
So if you are writing EJB 3.0 web services, you have a lot to gain by using BPEL and JBI in general, and you need to look into using the JavaEE SE. The following is a simple example of how to use it.
Read the complete post: http://jlorenzen.blogspot.com/2007/08/using-jbi-javaee-serviceengine.html