I am curious what code your host is referring to. I am using the integration maintained here at the Moodle for New Zealand schools site (I run a Moodle for a school district in Southern California). They even have a release for 2.5. It uses gsaml for authentication. For this integration package, most of the documentation you linked to is still valid.
Please post back with how this turns out for you. I am sure other Moodle admins will run into a similar situation.