login settings not showing ldap option

I have a fresh install of 2.5 and when I go to the login setting page, only BIT Auth is available in the drop down. It appears taht the ldap file is available under user/auth.

Any ideas where to go from here? Is this feature supposed to work in 2.5? The docs online are incomplete.

Happy to update them if I can get a little direction here.

root@host auth# ls -al
total 56
drwxr-xr-x 7 apache apache 4096 Jan 26 12:42 .
drwxr-xr-x 8 apache apache 4096 Feb 4 02:26 ..
drwxr-xr-x 2 apache apache 4096 Jan 26 12:42 bit
drwxr-xr-x 2 apache apache 4096 Jan 26 12:42 imap
drwxr-xr-x 2 apache apache 4096 Jan 26 12:42 ldap
drwxr-xr-x 2 apache apache 4096 Jan 26 12:42 locate
drwxr-xr-x 2 apache apache 4096 Jan 26 12:42 multisites
root@host auth# ls -al ldap
total 28
drwxr-xr-x 2 apache apache 4096 Jan 26 12:42 .
drwxr-xr-x 7 apache apache 4096 Jan 26 12:42 ..
-rw-r--r-- 1 apache apache 6194 Jul 20 2008 auth.php

For the LDAP option to be listed PHP needs to have been compiled with LDAP support. Check PHPinfo to see if PHP was compiled with LDAP support.

I thought I got AuthenticationPluginLdap quite complete ... you need the PEAR:Auth module as well before ldap is enabled.