Thanks, I found it. "This 'external' DPSK operating mode requires a significant amount of RADIUS server
development effort. This effort is unique to each customer or partner to
differentiate their onboarding workflow and services."
Seems like they don't want us to be able to configure it ourselves yet. I checked out the option, but enabling it seems to just put all the work on the RADIUS server. And without knowing how to configure it for external DPSK, there is no way to make it work, without offical documentation.