Using M-Audio Fast Track C400 Audio Interface for FaceTime but only input 1 audio is coming through?...

I'm trying to use my M-Audio interface for FaceTime/U Stream for music purposes. I'm a professional recording artist and I'd like to do some "live stream" concerts for fans from home. I have my keyboard in input 1 and my microphone in input 2. Both signals come through just fine when I'm using Garageband or Logic, but for some reason when I select the interface as the "microphone" option when streaming, only audio from input one is heard from my viewers. I've also switched the keyboard and mic to rule out the mic being the problem, but then the mic audio comes through and not the keyboard...I'm wondering if I'm missing some minute setting somewhere?...I don't understand why it's only for video chat applications that it's only receives one channel of audio...Any help would be appreciated, thanks.