While trying to test a fix for a remote ejb issue I have found a problem with pooled-connection-factory credentials.
It appears JBoss 7.1.2 nightly snapshot (16th April 2012) has tightened up security somewhat such that credentials are now required for internal pooled connection factory.

I have found that user credentials specified for the hornetq configuration are not persisted between server restarts.

For example. In the following configuration my server starts correctly the first time.
However the <user> and <password> elements are mysteriously deleted by the app server.

<jms-connection-factories>
<pooled-connection-factory name="hornetq-ra">
<transaction mode="xa"/>
<connectors>
<connector-ref connector-name="remote-jms"/>
</connectors>
<entries>
<entry name="java:/remote-JmsXA"/>
</entries>
<user>jmsUser</user>
<password>mypass</password>
</pooled-connection-factory>
</jms-connection-factories>