Use ident sameuser?

Is anyone using AUTH_TYPE=ident with AUTH_ARGUMENT=sameuser in the
PostgreSQL Host-Based Access file ("pg_hba.conf")?  The documentation
within that file says this:

#               AUTH_ARGUMENT is required:  [...]
#               The special map name "sameuser" indicates an implied
#               map (not in pg_ident.conf) that maps each ident
#               username to the identical PostgreSQL username.

However, with PostgreSQL 7.2 (on Red Hat 7.2 Linux 2.4.7-10) the
following lines do not permit access to PostgreSQL usernames identical
to system usernames [1]:

local   all                                     ident           sameuser
host    all     127.0.0.1       255.255.255.255 ident           sameuser

Only when an expressed map is present in "pg_ident.conf" do I get the
"sameuser" functionality, for example [2]:

admin        postgres    postgres

[1] The postgresql log message is 'FATAL 1: IDENT authentication
failed for user "postgres"'.  The system log, though, shows
'identd[...]: reply to 127.0.0.1: 2438, 5432 : USERID : OTHER
:postgres'.

[2] The log message is, for example, 'DEBUG: connection:
host=127.0.0.1 user=postgres database=mydb'.
--
     -William
This system has been running 47 days since the janitor knocked it over.
When did you last reboot Windows?