Instructions for using this with Sonar (from their website):
1. Copy VST pluging to your VST folder.
2. Launch Sonar. It should automatically recognize the new plug-in and create needed registry entries (ie you should see the plug-in as an effect in Audio FX menu). If not, use Plug-in Manager to scan new plug-ins.
3. Use Cakewalk Plug-in Manager, find MIDI Guitar in Effects section and open "Plug-in Properties". Enable "Configure as synth" option.
4. Close Sonar and use Regedit to change generateEvents key from "0" to "1" in HKEY_CURRENT_USER\Software\Cakewalk Music Software\SONAR Producer\Cakewalk VST X64\Inventory\ -> MIDI Guitar
5. Launch Sonar. Add new audio track. Insert MIDI Guitar (now found in Soft Synths menu) to FX bin.
6. Go to Synth rack view. Right click grey area of the MIDI Guitar synth block and click "Enable MIDI Output".
That's it. Add your favourite synth to a new track and route MIDI input from MIDI Guitar, which should be visible in MIDI input menu.