Actually, it appears to not be a bug so much as a general problem with deploying EARS with WARS.
The solution to the problem above is simple:
1) Use JBoss2.4.4 and Catalina 4.0.1
2) Put struts.jar, commons-xxxx.jars in WEB-INF/lib inside the WAR file and NOT in the common classpath of Jboss (lib/ext) (which is where I had them previously)
3) Put properties file in WEB-INF/classes/my_props.properties