When the 828 driver is setup in Logic, it defaults to a NO-digital in or outs set up so you must
1) Launch the 828 control panel
2) at the bottom there are 2 options - 1 says Optical input and 1 Optical outputs and it will say off -
3) choose TOSlink for Optical ins and Outs
4) hit O.K.
5) Launch Logic
6) go to your mixer page
7) now each of your Audio tracks that you want to go to the digital out, please choose OUTPUT 9-10 which will send that track to the digital outs...
and you are on your way....