Sonar lists available channels as a pair and labels with odd numbers. You should be able to choose left or right channel respectively.
If panning doesn't effect the sound heard, you may need to "Link" your DAW channels in Universal Control or Bypass UC Mixer.
Open Universal Control and click the image of the Studio 192 to open the Mixer view.
Click the Settings cog wheel in the upper right hand corner of the mixer view.
Test panning in Sonar. Should be good now.