Ok, so no suggestions from anyone, but got this reply from Cakewalk which has worked, so hope it helps someone else!
Your VS-100 should be configured as follows:
- First, go to Edit | Preferences, and under the MIDI Category choose Devices and enable the boxes for MIDI (VS-100) and Control (VS-100) under inputs and outputs.
- Hit Apply in Preferences.
*NOTE* If you do not see VS-100 drivers in Devices, close SONAR, turn the VS-100 off, and unplug the USB cable from the VS-100. Make sure that the VS-100 has Storage Mode set to Off. (To access Storage Mode, turn the VS-100 back on, then push and hold the Display button, and scroll to Storage.) Plug the USB cable back in and turn the VS-100 on before launching SONAR.
- In the Preferences go to Controllers/Surfaces.
- Click the yellow star button to add a new Controller/Surface.
- Choose VS-100 for Controller/Surface and Control (VS-100) for both the Input and Output Ports, then hit Apply and OK.