<p>Spring DA helps in writing DAOs. When using iBATIS as the persistence framework, and extending SqlMapClientDaoSupport, a SqlMapClient mock should be set for the DAO, but I can't do it. SqlMapClientTemplate is not an interface and EasyMock cannot creates a mock for it.</p>

DAO and unit tests do not get along well !
That does not make sense to mock anything in a component that does not hold any business logic and is focused on database access.
You should try instead to write an integration test. Take a look at the spring reference documentation, chapter 8.3 :
http://static.springframework.org/spring/docs/2.5.x/reference/testing.html