I don't think it is possible. However, why not run the backing tracks on output1, Virus on output 2, and have the virus generate a click to output 3? You would need to use multi mode and program a very simple single oscillator click sound.
Yes, it is the way of doing this. In Multi or SEQ mode. But it is a workaround - there's no way to put anything more on click track (like voice counting, etc.). I'm also not sure if everything work stable when changing sounds during the song.
So the 3 DAW Audio out still would be great - maybe in next firmware? 
(Do Access programmers look here?)
Is there a way to output DAW audio using Output 2 or Output 3? I'm playing a gig in a week with Virus TI2 and would love to run backing tracks using Output 2 and click (for the drummer) using Output 3 while playing synth parts on Virus using Output 1. Is it possible? (I can't find Out 3-6 in DAW's Output window). If not - was it possible ever (maybe different drivers or firmware)?
Access - are there any plans for such improvement?
the audio interface has a stereo configuration only. assuming you're fine with that you could use output 1 for your ASIO tracks and output 2 for you synth.
best, marc
