first post

I'm playing a Korg i3 and I've just bought an expression pedal / controller.
I've succesfully set it up for volume control, but can't figure out how to or wether this is possible at all: can I use that pedal to change another voice (program) parameter, i.e. the attack speed of a violin or string enseble?
I can't find anything on the board and in the manual about that - but I feel I didn't check everything out.