This may or may not help but I use an external VoiceWorks Plus sometimes and here is how I have it set up.
I have a V-Studio 700 and I connect a SPDIF from the interface to the digital in of the VoiceWorks and a SPDIF back from the VoiceWorks to the digital in of the interface. In Sonar, I create a SEND from the original track and one of the choices in the drop-down is the digital out of the interface. I create another audio track to receive the input and set its input as the digital in of the interface.
You could just as easily use a normal audio in and out instead of digital. I used the digital ins/outs simply because I have keyboards or mics plugged into all my available audio inputs in the V-Studio and I didn't want to yank cables everytime I wanted to use the VoiceWorks.
In the VoiceWorks, I turn off the dry signal so all that's coming out of the unit is the processed copy. Sorry that I don't know your particular model. In the VoiceWorks, you can edit a preset to set the levels of the various harmony/doubling parts and the level of the dry (original) voice. I have to get the manual out if I haven't used the unit in a while.
So, to recap:
- SEND from your original vocal track to whatever audio out or digital out is going into the TC Helicon.
- Turn off the dry (original) voice in the TC Helicon.
- Connect the output of the TC to your interface.
- Create a new audio track in Sonar and set its INPUT to the input on your interface that is receiving the TC.
- The TC is very sensitive to level so make sure what you are sending it meters strong without hitting the red.
- Likewise, you will have to use the trim (or input sensitivity or whatever your interface calls it) to make sure you get a strong, clean signal back.
I had to mess with levels a little to get things working but now it is set up whenever I need it. I got frustrated a bit but now it's good to go.
I think I have a post here somewhere describing this process.