Button names to indicate a task is paused or completed

I'm designing a form-based UI and the user can choose to leave things part-way through and resume later, or he can carry on to completion (in which case certain validation takes place). It's a little like filling your shopping cart on Amazon.

I need wording for the buttons which conveys those two situations to the user, but my user tests indicate that 'Save' and 'Finish' don't unambiguously do this.

So I can test the rest of the design, I've resorted to these:

but they do seem a trifle long-winded ;-)

I've seen the discussion about 'Done' and 'Save' but IMHO that doesn't really resolve the issue.