Help with RULE

On Postgres 7.1.3(SUSE Linux 7.0 - 2.2.16) I have this problem:

I have table, for example:

CREATE TABLE tbl_test(
id INTEGERE PRIMARY KEY,
...
_parent INTEGER REFERENCES tbl_test ON DELETE CASCADE,
...
)

Next, I create rule for table tbl_test on event ON DELETE:
CREATE RULE rule_test AS ON DELETE TO tbl_test DO INSERT INTO ...;

Why RULE doesn't DELETE recursive(for a consideration REFERANCES)!?

Please HELP ME!

Thank you

-- 
Otakar KLEPS               AVONET, s.r.o.
-----------------------------------------
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