wp_authentiate_user, check_password, LDAP and missing documentation

Hello,

I am trying to use WordPress 2.7 with LDAP authentication. Unfortunately, wpDirAuth doesn’t work on 2.7. Thus, I wanted to build a new, 2.7-compatible LDAP plugin.

Looking around, I came across the filter wp_authenticate_user, which possibly can be used to perform authentication. However, I only found this filter in the source code and in a brief mentioning at adambrowns website.
Neither gives a description of whether this is the correct hook to use or what a filter function should return.

Looking further through wp_authenticate(), I also found a mention to another filter check_password, called from wp_check_password. Would that be the correct place to perform LDAP authentication?

Additionally, the user information needs to be copied from LDAP. Should this also be performed in whatever filter will be used to perform the actual authentication or would this break the design of wordpress?

Many thanks in advance to anyone willing to help!

Regards
fantux