Hey,
just realised the same issue. Until now I only did send control voltages with Reaktor. For that the VST-Instrument version works as expected. Now I wanted to drive an external synth with pitch and gate. And faced the same problem as discribed by the Op. No oscillator calibration without input.
So I did setup a 5.1 FX Channel to use 6 outputs of reaktor and have an input for calibrating the oscillators. Now within the 5.1 Channel I am setting up 6 sends to feed my expert sleepers ES3. Works all well, but to be able to send the 6 discrete streams, I have to solo the respektive 5.1 channel in the pan-routing of each send. Which works, buuutttt, the pan-routing is not stored with the project nor within a channel-preset.
So did anybody of you find a solution that is not as boring as manually restoring the solo-status of all 6 sends every time I am launching a project. Tried using audio tracks too. But it leads to the same issue, because you have to create 5.1 audio tracks to receive anything from the 5.1 Send FX. And within these audio tracks I am only able to select a certain channel stream by soloing it in the input panner. And this status is not stored as well.
I am on Cubase 10 by the way, although it probably does not matter with this issue.
Thank you,
Oliver