Help with rules

I need some help. I was looking at this e-mail
(http://archives.postgresql.org/pgsql-performance/2005-06/msg00369.php)
and it gave me a good idea on how to fake partitioning.

I have created a test database with serveral identical tables.
Table_2003, Table_2004, Table_2005, etc

I then created the view "test_view" and defined as a union all of all
of the tables.

I have created several do instead insert rules trying to force the
data into the correct table when I load from production data into the
view/tables. However, PostgreSQL will not preform the inserts when
trying to load the data. It complains about needing an uncondition ON
INSERT DO INSTEAD rule.

Is there anyway to have a rule that would correctly insert the data
from the view into the correct underlying table when loading a file
with several years of data?

Thanks,

Chris