Trouble with strange OUTER JOIN syntax

I'm trying to port a program written in ESQL/C for Informix to
PostgreSQL using ecpg [ecpg is a great helper here, despite its
shortcomings]. Right now,  I'm having a hard time with OUTER JOINs,
even when using newest PostgreSQL-7.1.1.

How would you translate the following SELECT statements with
outer joins to PostgreSQL syntax?

SELECT ...
   FROM tab1 alias_tab1, OUTER ot1 alias_ot1, OUTER ot2 alias_ot2
   WHERE ...

SELECT ...
   FROM tab1 alias_tab1, OUTER (ot1 alias_ot1, ot2 alias_ot2)
   WHERE ...

It is even possible to have multiple tables specified at FROM
before the OUTER keyword, like here:

SELECT ...
  FROM tab1 alias_tab1, tab2 alias_tab2,
       OUTER ot1 alias_ot1,
       OUTER ot2 alias_ot2
  WHERE ...

SELECT
  FROM tab1 alias_tab1, tab2 alias_tab2,
       OUTER (ot1 alias_ot1, ot2 alias_ot2)
  WHERE ...

Another situation is here (same table 'otboth' with two aliases):

SELECT ...
  FROM tab1 alias_tab1, OUTER otboth alias1, OUTER otboth alias2
  WHERE ...

I didn't find any clue in Bruce's book nor in the postgreSQL docs/faq
as of 7.1.1. If at all possible, I'd like to stick to OUTER JOINs
because they are used extensively throughout the program.

Thank you for your help,

-Farid.

--
Farid Hajji -- Unix Systems and Network Admin | Phone: +49-2131-67-555
Broicherdorfstr. 83, D-41564 Kaarst, Germany  | farid.hajji@ob.kamp.net
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