Best practices for storing PHP sessions with a couchbase cluster?

I'm new to Couchbase and I'm evaluating it as a store for our PHP sessions. I followed this tutorial:
http://www.startupnextdoor.com/2011/11/how-to-cache-php-sessions-in-memb...

In that setup, PHP is configured to use 'memcached' as the session.save_handler and points the session.save_path at the host:port of the single couchbase instance. Seems to work okay but I have a question regarding SASL authentication. I dropped the default bucket and re-created it with a password. I'm seeing sketchy documentation as to whether the aforementioned php5-memcached library can talk SASL, and if so, how would I configure session.save_path to perform this authentication? Would I need to write a custom handler that uses Couchbase's PHP client and make use of session_set_save_handler() ? Or can I somehow otherwise use ext/couchbase ?