Deploying MDBs with jboss.xml descriptor specifying the mdb-client-id causes the deployment to fail with an IntrospectionException. The problem is that line 87 in
server/src/main/org/jboss/ejb/plugins/inflow/JBossJMSMessageEndpointFactory.java specifies the clientId property as clientID. Changing it to clientId fixes it.

Caused by: java.beans.IntrospectionException: No property found for: clientID on JavaBean: org.jboss.resource.adapter.jms.inflow.JmsActivationSpec@d8c235(ra=null destination=null destinationType=null tx=true durable=false reconnect=10 provider=java:/DefaultJMSProvider user=null maxMessages=1 minSession=1 maxSession=15 keepAlive=60000 useDLQ=true DLQHandler=org.jboss.resource.adapter.jms.inflow.dlq.GenericDLQHandler DLQJndiName=queue/DLQ DLQUser=null DLQMaxResent=5)
at org.jboss.util.propertyeditor.PropertyEditors.mapJavaBeanProperties(PropertyEditors.java:354)
at org.jboss.util.propertyeditor.PropertyEditors.mapJavaBeanProperties(PropertyEditors.java:285)
at org.jboss.resource.deployment.ActivationSpecFactory.createActivationSpec(ActivationSpecFactory.java:129)
... 137 more