Problems Testing User-Defined Function

Hi list,

I'm a newbie and I have a problem. I've defined the following function using
pgAdmin but I am clueless as to how I can test it. I will eventually be
calling this function from a .NET application but I want to test it using
raw SQL first. Here's the function definition:

CREATE OR REPLACE FUNCTION sp_insert_manifest(_sender varchar(255),
_sender_email varchar(255),
_reply_to varchar(255),
_filename varchar(255),
_file oid,
_datetime_sent timestamp) RETURNS integer AS $$

-- blah blah --

$$ LANGUAGE plpgsql;

I am trying to pass the following values to the function but I have been so
far unsuccessful.

SELECT sp_insert_manifest('me', me(at)you(dot)com', 'me(at)you(dot)com', 'test.txt', NULL,
'2006/06/09')

Can anyone help me here?

Thanks,
Rommel the iCeMAn.