LazyInitializationException inside JTA transaction

[lsalves]

I'm using JBoss 4.0.3SP1 whit EJB3 and MyFaces.

In a JSF managed bean, my application begin a JTA transaction and invoke a stateless session façade that return a entity bean. The entity bean has a lazy collection that throws org.hibernate.LazyInitializationException when I try to get it at managed bean method.

Follow the managed bean method:

public String consultar() throws Exception {
 ServiceLocator locator = ServiceLocator.getInstance();
 UserTransaction tx = (UserTransaction) locator.lookup( "java:comp/UserTransaction" );
 tx.begin();

 try {
 AplicacaoFacade facade = locator.lookupEJB( AplicacaoFacade.class );

 // Get informations for page
 vo = (UsuarioVO) paginaRegistros.getRowData();
 Usuario usuario = facade.getUsuarioPorId( vo.getId() );

 // Build organizations collection
 List<Long> organizacoesId = new ArrayList<Long>();

 // THROWS LAZY EXCEPTION !!!!!!
 for ( Organizacao organizacao : usuario.getOrganizacoes() ) {
 organizacoesId.add( organizacao.getId() );
 }

 tx.commit();
 }
 catch ( Exception e ) {
 tx.rollback();
 }

 return Constantes.OUTCOME_SUCESSO;
 }

The session façade uses dependency injection to get entity manager:

@Stateless
public class AplicacaoFacadeBean implements AplicacaoFacade {

 @PersistenceContext EntityManager entityManager;

 public Usuario getUsuarioPorId( Long usuarioId ) {
 return entityManager.find( Usuario.class, usuarioId );
 }

Why is it happening? Shouldn't entity manager be open until JTA commit ou rollback?