When you first select Digidesign Direct I/O in Digital Performer, the DIGI001 digital ins and outs are not enabled. You will only see the 1st Analog ins and outs.
The way to change this is to go to the WINDOWS directory and choose AUDIO BUNDLES and OUTPUTS . You will see Analog 1-8 listed there in black with a blue box in the ACTIVE field. You will also see ADAT 1-8 listed there and they are grayed out. To activate these channels you must put a blue box in the corresponding next open channels which would lead you 9-16
The same goes for your inputs as well