Can I use Sonar to test my audio interface SPDIF out and back in loop?

I'm trying to use the spdif on my audio interface for the first time and experiencing some difficulties with hardware connectivity I think. I'm wondering if I can trouble shoot from within Sonar. I have a focusrite Saffire Pro 10 io that works fine connected to Win 7 PC running Sonar X3. I am trying to use the SPDIF output of an ART Digital MPA II into the SPDIF input of the Saffire then into Sonar. I've not been successful and actually each time I try connecting them, the Saffire seems to keep restarting. I've tried various matching sample rates with the same results.
 
Focusrite tech support suggested testing the SPDIF input by looping the SPDIF output to the input on the Saffire and routing audio out and back in and seeing if I could record that audio. My question in regards to Sonar is can I do this all within Sonar? In other words can I say, import a stereo audio track and assign it's output to the SPDIF of the Saffire and arm another track to record with it's input set to the SPDIF of the Saffire device?
 
I've tried and it doesn't seem to be working, should it?
 
Thanks in advance!
 
Tim

I used a Mindprint Diport with a similar setup som years ago - spdif out to dac in Diport and spdif input from it as well.
 
Things to look out for is which is master and slave in the connection - soundcard settings.
And if 44k or 48k.
And also if this unit is turned on or not will affect how soundcard sync it all.
 
Then Sonar has a sync setting for record and playback - which input clock is used.
 
So it's just trying out these what works the best - but focus on soundcard first of all.
And in Sonar if looping back - don't activate Echo monitoring since it may cause feedback issues.
I'm most familiar with RME cards and don't remember how Focusrite handle sync.

Thanks for the help/suggestions. After testing per focusrite's suggestion, it appears the input on the Saffire may not be working correctly. Back to see what they say next.