The org.infinispan.transaction.lookup.JBossTransactionManagerLookup class doesn't work in JBoss 7 (at least out of the box) because the TransactionManager JNDI URI changed. It used to be java:/TransactionManager and now its java:jboss/TransactionManager. For now I've created my own lookup to find the JTA TransactionManager calling it JBoss7TransactionManagerLookup.

Not sure if a separate class is necessary ultimately; but maybe have the JBoss one look up both URIs?