The way JBC 2.0 is integrated into AS 5 is fairly different from the AS 4.x / JBC 1.x way. It's still a work in progress; in fact it's what I'm doing right now for the 2.0.0.CR2 release that should be out this week.
Couple things you can do:
1) Deploy your cache using a JBoss Microcontainer -beans.xml file. An example of that can be seen in the AS deploy/jboss-web-cluster dir. The jboss-web-cluster-beans.xml file creates an instance of PojoCacheJmxWrapper and registers it in JMX at jboss.cache:service=TomcatClusteringCache. PojoCacheJmxWrapper exposes an MBean attribute "PojoCache"; getting that attribute will get you a ref to the underlying PojoCache.
2) Wait for CR2 and upgrade the JBoss Cache version in your AS. (Can't promise there won't be issues with this; I'll find out later this week.) From that you'll be able to use an old-style -service.xml file. Key difference will be the value of the "code" attribute in your mbean will be org.jboss.cache.pojo.jmx.PojoCacheLegacyJmxWrapper.
The docs on this stuff will probably be fairly bare bones in 2.0.0.CR2; will be better in CR3 or CR4.
Thanks for your quick response. I'll do it in Java code for now then.
Yep. I was going to post back this morning saying I forgot the 3rd option of doing it programatically. :)