pam authentication - Mailing list pgsql-general

I am making a first attempt at getting pam authentication working with a
postgres 8.2.4 installation on suse 10.2.  I have created the file:

/etc/pam.d/postgresql:
auth    required        /lib64/security/pam_ldap.so
account required        /lib64/security/pam_ldap.so

and in my pg_hba.conf, I have the line:
host    all         all         0.0.0.0/0             pam postgresql

When performing login, I get in the server log:
LOG:  pam_authenticate failed: Conversation error
FATAL:  PAM authentication failed for user "testuser"

Worse yet, I am granted access to the server!

Any suggestions on what is up?

Thanks,
Sean