Instrument functionality is planned for the [G] button.
There may be a bit of an issue with checking the instrument number being pointed to:
https://forum.renoise.com/t/unreachable-properties-of-the-instr-automation-device/44690
but as far as I can see, it should be possible to loop and tell which parameters are available and replace the first unautomated assignment with the moved parameter in the VSTi/ plugin.
I haven’t proved concept yet, but will have a go. It won’t be as easy as standard devices, as you have to mess around with presets and their xml strings for this one.