Logic 7 Express / External Fx Processor / Spdif, Help me get L7E to talk to FX over SPDIF Options

[StrutterAtlanta]

I'm a new Logic user trying to get Express to talk to my MPX500 Effects processor using the S/PDIF connection. Everything is connected properly through a Presonus Firebox, and I have no trouble recording on inputs 1 - 4 of the Firebox into Logic Express.

However, I can't figure out how to route a track to the external processor. In PTLE it was a simple matter of choosing to send signal to the SPDIF outs as if it were another plug-in. I don't understand how Logic chooses to handle it.

I've poked around in the Audio Mixer with Audio Outputs and Audio Inputs but I still don't see how to send signal I've recorded on one of the audio tracks to the FX processor.

Can someone enlighten me in clear, simple steps a Newbie can understand?

Thanks!