I tried using BTM transaction recently,so I'm able to see processes in web console but after entering username and submitting first form,it throws exception related to datasource /transaction related exception.
If you have not changed lookupclass poperty in persistence.xml, you would get an exception as it assumes you are using Jboss transaction manager (see below), whereas you have configured Bitronix.
<property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.JBossTransactionManagerLookup" />