828mkII and 8pre question

I'm trying to run my 8pre as an additional 8 inputs to my 828mkII via toslink for recording in Cubase 5. My problem though, is that the 828mkII doesn't seem to recognise the toslink inputs, but the LEDs for the SPDIF keep spiking as if there's input from there, accompanied by a loud distorted static sound, but the lightpipe is the only input and this only occurs when it is connected
Could anyone suggest a solution? My ultimate goal is to have a total of 10 simultaneous inputs with the ability to monitor directly from the 828mkII's headphone outs

well for one thin they dont have toslink.
they do have adat; maybe you're not using the right cable....
Here is a diagram ajnd the available ports:
http://www.motu.com/products/motuaudio/copy2_of_828/inout.html