Sorry – we don't have step by step instructions for this sort of thing, and in particular, without having your machine in front of me, it is hard to tell what the issues really are.
A few things to try (in order, as necessary):
1) READ THE MANUAL. If there is any specific thing that you don't understand, please ask.
2) Clear setup. UM p.77.
3) Go to the <external> page (UM p.49) and step through all the "assigns", and set "mode" to OFF.
4) See if the problem occurs (my guess is it won't).
5) Set one of the higher numbered assigns to your pedal. (UM p.49-50)
6) see what happens.
