public @Stateless class XXXBean {

@PersistenceContext(unitName="ImagineDB")
private EntityManager manager;

public void someMethod() {
   Dog dog = new Dog(); //dog is an entity bean;
   manager.persist(dog);
   manager.flush();
   //here I want new transaction
   manager.getTransaction().commit(); //this commands fails
   Cat cat = new Cat();
   manager.persist(cat);

}

}