Yes; we don't need to switch tools, but I don't see the harm in using different tools for what they're most good at. I find some value in the separation.
Now I see how to use Mockito in the JMock style of "assume no-one should invoke it". I don't know whether one can use JMock in the Mockito style of "let anyone invoke it". I suppose Nat or Steve could comment and tell us!