[grs]

my mix goes like this.
Everything is in real time, nothing is captured as waves.
The sequencer outputs all the drums, vocals, other vsti synth etc to my DA coverters into my mixer.
The virus is recieving midi from my sequencer at the same time, it's outputs are into my mixer also.
The stereo mix from my mixer is being recorded into my AD converters into my sequencer.
So you see the virus sound is 'analog summed' with the rest of the musical parts.
Also your other parts from you sequencer benifit from going out of as many channels of DA as possible to your mixer.