Automap 3.74 and expression pedal problem

Using Novation Remote 61 SL and Automap 3.74 in Sonar X1 Exp:
Does anyone know how to assign an expression pedal to a filter like the WahWah  in Guitar Rig 5 with automap ? I can easily assign any button, knob or slider to the wahwah, but the expression pedal (and sustain pedal for that matter) is greyed out in the automap window.
There is contact between my pedal and the controller keyboard, e.g. I can set up the pedal in edit mode and record data to a midi channel. Alternatively : is there a way to connect a midi track to the audio track that is assigned to Guitar Rig ? I don't see that option in the outputs of the midi track.
I spent a long time with this problem