Currently I have implemented a repository layer based on HibernateDaoSupport. I create a SessionFactory by using Spring’s AnnotationSessionFactoryBean. How do I get Spring Data repositories working in this environment?

You have to replace AnnotationSessionFactoryBean with the HibernateJpaSessionFactoryBean, as follows:

<bean id="sessionFactory" class="org.springframework.orm.jpa.vendor.HibernateJpaSessionFactoryBean">
  <property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>