Firewire 410 - Help Needed, Recording digital to Cubase Options

[tig66]

Hopefully someone can help.

I'm trying to record my old DATs via a Tascam D20 connected up to the S/PDIF input on a Firewire 410 into CubaseSX3 on Mac OSX 10.3.7 - the 410 user guide says to set the inputs within Cubase 'Device Setup' to the S/PDIF Digital input L and R - trouble is, I can't find the digital inputs in Device Setup as they're not listed - all I can see are 4 inputs labelled Firewire 410 Multichannel 1 - 4 respectively.

I can hear the audio fine from the audio interface directly to my monitors - but there's no signal going into Cubase..

How do I set Cubase to see the digital input from the Firewire 410?

Any help with this would be really appreciated!

Thanks