The installation & setup guide is a good starting point for use with Sonar, and covers the basics of the audio, VST and freeze setup..ie..
1. Instantiate Virus Control with the following options : synth track folder, midi source & synth outputs: stereo
2. When Virus has loaded, you can then insert additional midi tracks and then "move to folder" so that they all operate in the synth track folder. So your folder with be synth folder> three audio tracks + (1-16) midi tracks.
3. Select one of the Virus audio tracks and right click then >freeze>freeze options. Disable fast bounce, enable single bounce per track
Now, so far so good... but thats not the whole story....After working with X1 and now X2 with the Virus, and struggling to overcome non-aligned (latency) audio after freezing, my brain finally woke up 
For 20yrs midi tracks have started at measure 2.. at measure 1:1:000 the clock starts and a ton of control and setup info.. PC, pan, vol, mod, RPN & NRPN data can get junked into a synth.. and to do this at the same time as playing notes is, well... "illadvised" and you get what you deserve...so songs have typically started at measure 2.. this actually is recommended (i think) in the tutorial.
Now, I had issues of variable latency irregardless of audio driver settings and VC settings, then the clue was a delayed note... so while I am not saying that you will have any problem at all if you do, for troublefree operation of Virus Ti with Sonar X1 & X2 (and 8.5.3) simply ensure you do the following 2 things..
1. Start all songs at measure 2 (as you should for all midi work)
2. Ensure your Virus track clips extend to measure 1
Its part 2 there is the critical bit.... though I HAD started my project at measure 2, it seems that Sonar freezes the clips so the clip itself needs to extend to one measure minimum prior to Virus playing ... giving time for Sonar & virus to sync..
hope this helps