Reviving an ancient thread and all that, but I think I just figured this out. You need to extend an antenna to be able to use RCS on a craft with an OKTO as the pilot.
I'm on 1.2.9, and observed that if:
I was using an OKTO as a pilot, and
I did not have a green line to the space center on the Map view (fixed by extending an antenna,
Then:
RCS controls did not work
Fine engine controls did not work, only Z and X to use full/zero throttle
SAS would continue to use RCS for stability
Hope this helps!