digital i/o Firebox to Lexicon

[feyshay]

I'd like to be able to send from my Firebox to my Lexicon MPX 550 without going through the A/D and D/A conversion in the Lexicon. I have some nice conversion with my Apogee mini-me/mini-dac combo and don't want to muck it up too much with reconverting through this lower end Lexicon.

I want to record dry from my preamp into Live 5 and then send from Live 5 through my Firebox through its Spdif out to the Lexicon spdif in and then back into the Firebox from the Lexicon through spdif and record the processed signal(a resampling through the Lexicon). I can't get this working. I get this loop it seems where each device (the Firebox and Lexicon) are looking for the other unit to be the master clock (and neither asserts itself).
Any way to get around this. Any solutions?
Is this a limitation of the Firebox (do I need more than one digital i/o), Lexicon or both of them. How do you typically use an external effects device within a computer DAW, staying within the digital realm (with spdif connections)?