DJTB,
Think of your Virus when connected to your Mac with its USB cable as an extra sound card installed into your Mac via USB connection, because along with the MIDI, that's basically what it is.
Would your software be happy if you added/removed the soundcard on your Mac in realtime while it was running?
Try setting things up so that your soundcard (aka TI) is installed on your Mac and connected and running (on) prior to using the software, and that you've set the software up to use this soundcard as your primary one, and disabled any others you might have installed.
See if that logic works with your Logic.
