Topic: Fireface + RosettaStone

Hi,
I would like to use my Fireface interface together with RosettaStone (http://www.rosettastone.co.uk/), instead of built in usb mic/headset stuff.
I have connected a microphone to my fireface (input 1).. but Im not sure what to do next..

When I try to find the recording input device, roseattstone only shows my "high definition audio setup"-microphone.. and not fireface input devices..

Of cours I could use my usb mic/headset.. but would be nice to use my fireface+my pro microphone.

Thanks for any help.