How to log outputs from pl/pgsql into a file ?

Hi everybody.

I'm working un Linux SuSe7.0, Postgres 7.2 compiled from sources.

I have a function in PL/pgSQL and I have to write some infos on screen. For
that I use RAISE NOTICE ''Number %'',my_number;

It works fine on screen, but now I want to log it on a different file each
time (not the pog log). I've tried to make a shell (myshell) that calls the
script
psql mybase << EOF
select my_func();
EOF

and I make myshell > test.log

I only have the retrun of my function, and not the 'raise' that only appears
on screen. Idem if my shell is

psql mybase << EOF
\o test.log
select my_func();
EOF

and I have the same result. I guess it is possible ti have outputs written
into a file (like "spool file" in SqlPlus for Oracle) but I didn't find
anything on documentation for PL/pgSQL. Can I use raise notice for that ?
And how ? And what else can I use ?

Thanks a lot.

Regards,
Stephane.