Out of curiosity, what about the AIU connection method is not what you are/were after?
There is a lot of information presented in the diagrams...but if the objective is to replace the manual button-controller with the DCS Remote via AIU, I think it could be as "simple" as:
The diodes are required and while they are 5 cent components, after shipping and what not you could end up paying $1 or more per diode.
I can also imagine discipline is required with the AIU method so as not to "accidentally" turn ON both the motor up and motor down ACC ports at the same time. Obviously you want to use the DCS Remote's momentary "ACT" button to drive the motor in only one direction!