Hi Adrian
We are currently using 5.4.x snapshot version of console server due to a bug that wasn't fixed in the 5.3 human task service. The trick with the Hibernate errors was to turn on trace level debug in standalone.xml by adding an entry to the logging module:
<logger category="org.jboss.as.jpa">
<level name="TRACE"/>
</logger>
The log then usually contains enough information. We found that the persistence provider was definitely being read, as it was being used to create the database (and there were logs to that effect) but not found on first DML use.
Tim