Exception Handling with Spring's @Transactional

I'm developing a web app with Spring MVC and hibernate for persistence. Given my DAO where GenericDao has a SessionFactory member attribute:

@Repository
public class Dao extends GenericDao {
    public void save(Object o) {
        getCurrentSession().save(o);
    }
}

And a Service class

@Service
public class MyService {
    @Autowired
    Dao dao;

    @Transactional
    public void save(Object o) {
        dao.save(o);
    }
}

I want to inform my user if a persistence exception occurs (constraint, duplicate, etc). As far as I know, the @Transactional annotation only works if the exception bubbles up and the transaction manager rolls back so I shouldn't be handling the exception in that method. Where and how should I catch an exception that would've happened in the DAO so that I can present it to my user, either directly or wrapped in my own exception?

I want to use spring's transaction support.