SPDIF IO and Lexcion MPX-1

[spiral]

I'm trying to set up my Lexicon MPX-1 to use with live as an external effects box
I have connected the MPX-1 to my motu ultrlight using spdif
The mpx-1 registeres the incoming signal and if I use cue mix software and bring up the spdif faders I can hear the effected signal but no audio comes through into live
I have external effect set up to send audio out on channels 11/12 which are spdif and in on channels 11/12
Looking at front of ultrlight the meters say signal is coming back in but nothing comes through to live
all help appreciated
thanks

[spiral]

moved the eternal effect from a send to an insert and it works fine
which is odd

[spiral]

got it working - had io channel numbers wrong - DOH !!