[MarPabl]

From the linked thread (had to struggle to read it, bad link), your best option is this:
1. Use the Search button on your Viris TI so you can browse the Programs by Category.
2. The first (leftmost) soft knob allow you to change the Category. Select the Input category.
3. Use the Value +/- to browse the Programs devoted to external audio processing. There are even Programs with effects already applied, which will be a good starting point for you.
4. Connect the aux from the mixer to the Input of the Virus TI.
5. When you play a key, you'll be able to hear the incoming sound.
6. Connect the output of the Virus to the return on the Mixer.

With this, you're done. Now more specific details to allow you to get the incoming audio without having to press a key:
1. Press the Edit button which allows you to configure the Program as a whole.
2. Use the Parameter +/- until you find the section "Inputs"
3. Set the mode to Static. This way the envelopes are disabled and you don't have to press a key to hear the incoming audio.
4. For Input select, match where you plugged the signal (L, R, L/R)

Regarding the ability to also be able to use the Virus as a "normal synth", you need to go to Multi mode and from there you associate the Input Program to one Part and your "normal" Program to other Part. You should make sure to send the incoming signal to a different output on the Virus (you have 3) to avoid mising the effects processor and the "normal synth"

BTW, read the Atomizer Reference manual. This one will explain nicely this IIRC.