JWT authentication without DF user registration

The DF2 documentation states as OAuth 1.0, 2.0, LDAP and local user management as the options to be able to get JWT tokens and then use it for API calls during a session. What if I have a custom authentication & access server which can provide me with JWT tokens, how can I use it to call the DF REST APIs ? Will the DF2 JWT verification layer during each call be able to verify such custom JWTs (ones which have not been created by DF user service) ?
If not, can somebody provide pointers for such enhancements.