Sonarworks Systemwide works differently that Sonarworks Reference plugin, because it is located in a different position in your audio chain.
On Windows, Systemwide uses Direct Sound drivers, not ASIO. So that means if you wish to use the full potential of your external audio interface, then you will need to use your DAW with ASIO drivers and Sonarworks Reference 4 plugin.
On Mac, Systemwide still uses core audio drivers, but it limits the system that no inputs are available through the Sonarworks Systemwide Core audio driver. Which means you can use Systemwide for mixing and playback but not for recording any input in your DAW.
Systemwide does not support any inputs for recording, or multiple simultaneous outputs. It is a 0-input, 2-output virtual audio device.