voiceover and my microphone

I am trying to record voiceover in Final Cut Pro X using my apple headset which has a microphone in it. If I check "system preferences" and then "sound," I do indeed see that my computer is recognizing my headset as the input source. But then when I enter FinalCut and press "record voiceover" and look at the input options, the only option i see is "built-in microphone," and it is not picking up sound from the headset.

any help?

thanks

ilana