Drumazon. It's been a while since I used it, but are you saying you want to use the built-in sequencer, but change which pattern is playing as required?
To do that I suggest you use Drumazon in Host rather than Native mode.
You then need to set up a MIDI track with its output pointing at Drumazon (which should be in the list of MIDI inputs in the pull-down).
If you insert Drumazon as a synth without selecting a track, you get a pop-up window. In that window select seperate MIDI and Audio tracks.
That MIDI track is where you record the notes that tell Drumazon to change pattern. You don't need a keyboard controller to do this, you can just write the notes in the MIDI track using piano roll view. You can also put in any CCs you need as well.
To sequence in Sonar, then have Drumazon play the sequence, insert Drumazon as above. You then use PRV or the Sonar step-sequencer to sequence your patterns in the MIDI track. The MIDI track then tells Drumazon what to play.
You do not need to record the output of Drumazon because the audio track created when you inserted the synth will do that for you. You can also get a "copy" of the audio by using the "bounce to clips" or "bounce to tracks" function.
In Sonar (and every other DAW I can think of), VSTi routing works like this:
Controller (if used) -> MIDI track -> VSTi -> Audio track. An "instrument track" is actually combines the MIDI and audio track so it works as both. I prefer to keep them seperate as I find it easier to work with.
Is that any help?