I almost have it working, but though I don't have anything in my persistence.xml about exporting the schema when the JBOSS entity manager loads it exports my schema and wipes out the pre-existing database with it's initial load.
I don't think this happened with the standalone Hibernate Entity Manager.
19:52:38,203 INFO [SchemaExport] Running hbm2ddl schema export 19:52:38,203 INFO [SchemaExport] exporting generated schema to database 19:52:41,765 INFO [SchemaExport] schema export complete
if you don't set some settings in persistence.xml the default values from jboss-4.0.3\server\all\deploy\ejb3.deployer\META-INF\persistence.properties are used.
default here is: hibernate.hbm2ddl.auto=create-drop
so this should be modified by you or you have to set some specific value in your persistence.xml