No firewire out from STP

Hi:

Thought Soundtrack Pro should send audio out through the firewire connection to the deck. Only audio I can get out is through the computor's internal audio-out port. Lists the firewire set-up in the manual and I have checked all preferences I can find. Thanks, Tom

Dicovered that if the audio is under a video track, then STP will send it out thru firewire. If there is no video track, then audio is not sent thru firewire.