There are other options, but this is how I would do it. 1 way would be to add a send to each track to feed the appropriate output. Now you need to decide how to get these signals assigned.
Then open your IO setup and create output paths to the optical outputs(a stereo path for 1/2, 7/8 and 9/10, mono paths for the rest). Of course, the above is just a suggestion based on how I like to arrange things, so adjust to fit your preferences. (13, 14 and 15 can be left open or fill them as needed for any given recording project). Given the optical connection is 8 channel, you have 8 paths per lightpipe, so you might do something like this: Once you have the optical connection working, you now need to decide how to feed signals, and what you want to feed.
