Digitech Footswitch FS300 works fine with the KPA

I just found an old Digitech Footswitch FS300 and connected it with an 1/4" stereo jacked cable to the KPA, pedal 1. After adjusting the pedal-parameter in the system menu (page 4) to
1: Switch (stereo): Rig up/down it works fine as a simple footswitch. The Bypass-button on the FS300 can't be configurated - it curiously switches around the leds in the FX-block
But anyway it's a nice late function of the ol' box.