Soundtrack Pro channel mapping with a new setup

Hello All,

Looking for a bit of guidance regarding editing / mixing for 5.1 in SoundTrack Pro and Adobe Audition.

I had been editing with both pieces of software and had a successful 5.1 set up. I could place audio in each speaker independently via the software, and it would playback properly in the software and upon export.

Recently I've switched my setup from an old Klipsch ProMedia GMX D-5.1 (that was connected directly to the editing machine via optical), to a Denon 1610 receiver and Energy speaker surround setup (again, connected directly to the editing machine via optical).

The problem I'm encountering is that I can't get either piece of editing software to output properly and / or to the specified speaker / channel. Everything, all channels, are coming out of the Fl or Fr speakers. Playback of previously created 5.1 tracks (QT or .ac3 files), in QuickTime or VLC, are mapped properly.

What am I missing? I have a suspicion that the issue is the elimination of the Klipsch Digital preamp / control module. If this is the case, do I need a DAC that goes toslink in to toslink out and into my receiver? Id so, do you have any recommendations for a DAC?

Thanks.

Floyd