Ok, 18i20 and Behringer ADA8200 connected via ADAT and synced/locked at 44.1 kHz. If I use the S/PDIF in inputs 7 and 8 of the ADA8200 aren't available in Focusrite Control (greyed out). If I uncheck S/PDIF in in FC, then inputs 7 and 8 on the ADA8200 become selectable again. I feel I have met the requirements of syncing and locking the two units as described in the owner's manual and both units do work on available inputs. My friend with the same two units has the exact same results. Help!