Try the reverse - take a running EJB3 jboss and add in:
Also, may want to start clean and copy the /server/jbpm/data folder to override your EJB3's /server//data folder as it does not seem to auto-create the JBPM database at the moment.
This isn't foolproof as I'm presently having process archive deployment issues, but that may be just me ;-)
More full details with some original missing information:
For installing jbpm 3.2alpha2 on JEMS jboss 4.0.5.GA-EJB3 server.
*Copy to /deploy jboss-console.war
-modify jboss-console.war and remove /WEB-INF/lib/javassist.jar. This is already in the jboss AS classpath and will cause ClassCastExceptions.
*Copy to /deploy jbpm-ds.xml (may also want to overwrite the hsqldb-ds.xml from the 3.2alpha2 starter kit to the AS).
*delete $JBOSS_HOME/server/<>/data directory. Replace with $JBPM_STARTERKIT/server/jbpm/data directory.
*Copy the $JBPM_STARTERKIT/server/jbpm/conf/login-config.xml fragment "Other" policy to override the $JBOSS_HOME/server/<>/conf/login-config.xml "Other".
Start playing (testing) at http://localhost:8080/jbpm-console/