Custom per client configurable ClientAuthenticator

I succesfully created a custom ClientAuthenticator by extending an existing one. Next step is that I like to make it configurable per client. I implemented .getConfigPropertiesPerClient() but I can not find a way to let the admin render this config. The javadoc for gives a hints " Applicable only if “isConfigurablePerClient” is true" . But there is no isConfigurablePerClient() in the interface, only isConfigurable() which is for global config.

What am I missing?

Thanks, Ton