I'm looking at the MIDI documentation and I see the following:
26 - Delay On/Off
27 - Delay Mix
28 - Reverb On/Off
29 - Reverb Mix
68 - Delay Mix
69 - Delay Feedback
70 - Reverb Mix
71 - Reverb Time
It doesn't explicitly say, but 68 - 71 may be for performance mode only.
But if your foot controller supports sending messages on key down and key up triggers, you should be good to go. Otherwise, I don't know how the Kemper would fulfill this request. Maybe describe it in detail a little further.