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?