Extending FRAPI classes

[marty]

Hi again,

I was wondering if you could tell me what is the right way to extend
and use FRAPI classes. For example, you have the Oauth2.php
authentication class - but to enable that it seems like I need to edit
the Authorization.php because it explicitly loads the Digest
authorization method.. what would be the best way to maybe add
additional auth classes and use them - without modifying core too much
(would want to keep FRAPI easily updatable.. yes I love Drupal
hooks :))

Thanks!