I've got my HD500 working differently with the Kemper.
It's set to Pedalboard mode with Footswitches 1-8 sending only midi program change data; each selecting a preset on the Kemper giving me instant access to 8 Kemper profiles. I have preset 1-3 running like this with preset 4 set to send CC messages, toggling stomps and effects. You could create a hybrid but it's really easy to toggle between the patches on the HD500 to have good control.
The only downside is that it's one way communication so you get no lights on the HD500, which makes much less difference than you'd imagine.