LC_CTYPE and matching accented chars

Trying to understand how I can get Pg 8.2 to match 'martín' when I
search for 'martin', and going through the documentation, specially

http://www.postgresql.org/docs/8.2/static/locale.html
http://www.postgresql.org/docs/8.1/static/functions-matching.html

Here is a transcript of my commandline - I suspect I am quite close, but
something is missing. Hints _really_ appreciated!

# do I have a Spanish locale on this box?
locale -a
# no I don't - let's make one
sudo locale-gen es_AR.utf8
# check that I have it
locale -a
...
sudo pg_createcluster --locale=es_AR.utf8 8.2 arg
sudo pg_ctlcluster 8.2 arg start
sudo -u postgres createdb --cluster 8.2/arg testing
sudo -u postgres psql --cluster 8.2/arg testing
# in psql...
=# create table test (value text);
CREATE TABLE
=# insert into test values ('martín');
INSERT 0 1

# this is apparently the right way to
# select base character based on the "equivalence class"
# as defined in the LC_CTYPE
=# select * from test where value ~ 'mart[=i=]n';
value
-------
(0 rows)
# grumble - double check
=# SHOW LC_CTYPE;
lc_ctype
------------
es_AR.utf8

Any hints in general?

- How can I read the LC_CTYPE definition? IOWs locale-gen has created a
binary blob in /usr/lib/locale/es_AR.utf8/LC_CTYPE but I sure there is
a human-readable definition somewhere...

- Is that the correct syntax?

- Pg bug? I doubt many people are counting on this behaviour... as it
seems to be widely announced to be brittle and slow.

cheers,

m
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