Solution :
1 - Press the "advanced" button
2 - Press the control/pedal you want to program
3 - Press the Ctrl asgn key (E1)
4 - Using the numbered keys (G5-B6) to enter the number "66" (press F6 twice)
5 - Press the Enter key ( highest key, C7)
any midi CC value can be assigned with this process. Standard sustain, for example; is CC number 64