Spring @Transactional and inheritance

I do have a generics-based DAO class, which is base for all other DAO classes in my project and contains common functionality:

public class Dao<E> {

    private SessionFactory factory;

    public void setSessionFactory(SessionFactory factory) {
        this.factory = factory;
    }

    public E get(int id) {
        // ....
    }

    public void save(E entity) {
        // ...
    }

    public void delete(E entity) {
        // ...
    }

}

In my project I am using multiple datasources, pointing to different databases, therefore, I do have multiple session and transaction managers:

<bean id="factory1" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="dataSource" ref="source1" />
</bean>

<bean id="manager1" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="factory1" />
</bean>

<bean id="factory2" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="dataSource" ref="source2" />
</bean>

<bean id="manager2" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="factory2" />
</bean>

Now I want to create couple of DAOs, operating on different databases:

@Repository
@Transactional("manager1")
public class Dao1 extends Dao<Entity1> {

    @Overrides
    @Autowired
    @Qualifier("factory1")
    public void setSessionFactory(SessionFactory factory) {
        super.setSessionFactory(factory);
    }

}

@Repository
@Transactional("manager2")
public class Dao1 extends Dao<Entity2> {

    @Overrides
    @Autowired
    @Qualifier("factory2")
    public void setSessionFactory(SessionFactory factory) {
        super.setSessionFactory(factory);
    }

}

but the