SOLVED: Using external FX with Sonar Platinum & Scarlett 18i8 interface

Evening all -
 
I'm having a heck of a time setting up the proper routing to use my Lexicon MX300 with Sonar Platinum.
I've read through all the related manuals, but so far I just seem to be really good at creating feedback loops!!
 
I'm using the Focusrite Scarlett 18i8 as my audio interface, with the latest version of Scarlett MixControl software.
The Lexicon MX300 I/O is connected to the 18i8 via SPDIF I/O.
 
Both devices sync properly, and outside of Sonar, I can route external audio inputs to the MX300 by manually routing using the MixControl software.  So, the hardware and MixControl software appear to be working fine, but I evidently keep messing up something with the Sonar / MixControl integration.
 
EDIT:
Figured it out -
DAW outputs 7/8 routed to SPDIF Outputs 1/2 using MixControl.
After that was set, I used the External Insert Audio FX, with inputs & outputs routed to the SPDIF ports.
Enable Automatic Delay Measurement Control on External Insert, and all works great!!
 
RR