SPDIF Output

[Gregrb]

Hi, i have spdif cable plugged in to vrm from d8b output spdif, pro tools is connected to d8b on spdif input on d8b, when pro tools is playing levels show on d8b, tape input ch 25/26 and when master fader is turned up you get sound out of monitors and phones mix 1 & 3. But no output sound out of spdif to the focusright vrm? There must be some where i have to assign master fader output to feed to the spdif output. But how do I do this?