RME Fireface 400 and Yamaha 01v96 v2

Hi,

I just bought the RME to interface ADAT Optical (lightpipe) with the Yamaha mixer. What I need to do is plug an instrument into the mixer and have the sound output from ADAT on the mixer into Logic (Pro 8) via the RME interface. In Logic Audio settings I selected RME as input source and on the audio track I have inputs 1-18 available (paired if track is stereo). Now here's my problem - if I plug the instrument or microphone into RME, Logic receives the incoming sound but I can't figure out how to route the signal from the mixer into the RME interface when the instrument is plugged into say Input Channel 1 of the mixer. Looking at the display access PATCH on the Yamaha I see under OUT PATCH that Slots 1-16 are assigned to Bus 1-16 and ADAT 1-8 assigned to BUS 1 - 8. At this point I'm completely lost - RME is not receiving anything from the Yamaha. Does anyone have a clue what I'm going on about or trying to achieve - sorry, complete noob at setting up ADAT. Thanks