I'm not certain I can help, other than confirming that yes, the E-Mu Proteus modules definitely respond to expression via MIDI. And the response is global, not just per patch (so I don't think your answer is in the PatchCord parameters) I have an E-Mu B-3 module which I used to use for that all the time. (I slaved it through a DX21). I have since gotten a Proteus V6 keyboard and moved the B3 board into it, so I don't use expression through MIDI anymore but rather just plug the expression pedal directly.
Also, yes, all the Proteus 2000 modules share the same architecture is the same.