Drag an instance of omnisphere in to the track view.
Uncheck everything in the pop up, we are going to do all that ourself, click OK and nothing will seem to happen.
Hit B to open the browser, click the synths tab.
You should see Omnisphere there, doubleclick it to open it.
Click on MULTI.
Set first track in Omnisphere to CH1, OUT A, next track to CH2 OUT B etc... for all 8 tracks.
Now add an audio track to Sonar.
Click the Input drop down and select Omnisphere A Stereo for the first track.
Repeat for the rest of the audio tracks, just select Omnisphere B Stereo and so on.
Add a MIDI track to Sonar.
Click the out output dropdown and select Omnisphere, then set the midi channel on this track to 1.
Add more midi track and set the channel to 2,3,4 etc..
That should be it, add a folder track and stick everything in there so you can quickly fold it all up to keep things tidy.
Select the folder track so it's highlighted, click the little number on the track folder and it should turn blue.
Go to file:export:track template and save the track template, that will save everything in the track folder as long as it's selected when you select export.