It's a shame that it's not working with a USB A-B cable BUT I finally got mine working with a USB to Midi cable from ESi called: MidiMate eX.
Important: Change the midi channel setting from 1 to Omni in the Ampero app! Otherwise you have to step on the switch multiple times before it reacts. 
Hopefully Kemper and Hotone will work the USB A-B cable issue out soon.