Thanks for you hints! :] Unfortunately I'm not very good with the solder iron, so replacing controller is not a option for me (don't wanna risk ruining both keypads). Already figured there must be a way to do it via software (some sort of "man in the middle attack" via drivers -> distinguishing the two devices by port/ID or something, intercepting the input of one device, overwriting the input of one device, hand it over to windows... or directly via dedicated software that grabs the input, doesn't give it to windows, processes the input on its own). I`ll have a look into this thread you linked and do some research on my own. As soon Ill find a solution, I post back to share the info...