1) In your Audio preferences "DIRECT I/O" needs to be chosen...
2) once you chose that, chode the drop down menu of that driver
3) now hit the Hardware setup button
4) That brings a box that gives you 3 parameters CARD, SAMPLE RATE,And SYNC MODE - and OTHER OPTIONS
5) please hit the OTHER OPTIONS button
6) when you hit that you will see and EQ and some other parameters
7) please make sure that your SPDIF comaptibilty parameter says "OTHER"( the other choice is DA30)
8) and your Optical format parameter says ADAT
9) hit Done, and that brings you back to the original page
10) hit DONE again
11) go back into the HARDWARE SETUP button again and the 3 parameters should read as follows
CARD -Digi001
Sample RATE - 44.1k
SYNC source - SPDIF/RCA
12) then hit Done
13) now there is also another parameter in your DIRECT I/O driver menu.
14) please check the "USE 16 or more ins and outs" Box
15) Now open up your MIXER page and go the track in question
16) you should now be able to choose input 9/10 which should be your SPDIF inputs -
17) record enable the track
18) Monitor the signal...

you are on your way.....