Hello, I am using NI Guitar Rig within a Sonar project.  It's been a long time since I last used this feature and it's not working as expected.
 
Guitar Rig is a VST audio effect (as opposed to a VSTi).
 
I create an audio channel. 
Put Guitar Rig in the FX Bin for the channel.
Input is set to the guitar input.  I arm the track and can see the meters responding to the playing.
Sadly, Guitar Rig does not see any input signal.
If I enable "input echo", now I can hear the input to the track AND it also is fed to Guitar Rig.
 
The problem is that the only way to feed the input signal to Guitar Rig seems to be enabling input echo.  It feels like a bug, but its probably a stupid setting in sonar that i forgot.  Why on earth, when the track is armed (and input echo disabled) does the plugin not get any signal?  I can see the meters moving when the track is armed.  The only way to get the signal to pass to the plugin is to enable echo, but then im hearing the original signal and the effect.  Makes no sense.
 
The "bug" is that there is obviously an input signal but for some reason its not passed through to the plugin until echo is enabled, and it is not desirable to hear the input signal AND the plugin (just want to hear the plugin).
 
 
 
 
 
 
 

With the track armed, metering is on the input, but FX plugins operate on the output, and without input monitoring enabled, the input signal is not passed to the output. If you're hearing dry signal, it's being passed through the plugin, and you need to check the wet/dry mix.

Perhaps an understanding of how SONAR actually captures your guitars audio would help.

With your Guitar plugged into the input of your Audio interface, when you hit record SONAR and CbB capture your guitar Raw i.e. no FX is printed to the captured Audio.  Unless you have FX between your Guitar and interface.

Then when you play back the recorded Audio you will hear the effect of any FX in the FX  bin or Pro Channel.

If you want to hear the effect of those FX you need to tell SONAR or CbB to let you hear them, this is enabled by engaging Input Monitoring (input echo).

With is enabled, the Audio is still capture Raw, i.e. the effect of anything in the FX Bin and Pro channel are not printed to the audio but you hear their effect in you monitors.

Main advantages of this method is that you can change the FX or amp simulation at any point without having to rerecord as the audio is untreated right up to the point until you Bounce the project to stereo or whatever you bounce it to.  Even after you have completed a mix and exported the finished track the original audio is still held in SONAR or CbB Raw.  Enabling you to go back and make changes at any point.