Nobody likes to read manuals including me. Once I almost killed myself because I didn't read the manual. I am not going into the detail because it is embarrassing. The procedure was so simple (if you read the manual).

Anyway, you can do so much more with a MIDI foot controller. Fortunately, most of the Korg arrangers if not all can be controlled by just about all MIDI foot controllers. I noticed that my SD40 only uses SySex messages, and only a few high-end MIDI foot controllers can be programmed with SySex messages and send them out. These can be over $1,000. I have a Gordius Big Little Giant2, but it's kind of bulky. I was looking for a smaller one and found this
http://www.midiflorian.com/#service. It will work on Korg but not on Ketron as it doesn't send SysEx. The owner says he might support SysEx in the future.