That is not available in Moodle 2.1.
In Moodle 2.1, if you choose 'Interactive with multiple tries" for how questions behave, this is what happens:
- The student sees the question with a space to put in their answer, and a 'Check' button.
- If the student enters their answer, then clicks check, and their answer is wrong, then they get a hint and another go.
That is, the student has to try to get the question right, rather than just click a 'Hint' button, in order to get a hint.
If someone wanted to try to implement the behaviour you want in Moodle 2.1, then that would be possible, becuase 'Question behaviours' are a type of plugin. It might be no more than a few days work, for someone who knew what they were doing. http://docs.moodle.org/dev/Developing_a_Question_Behaviour
(I'm afraid I don't have the time.)