can not create trigger with parameter

Hi,

I'm having trouble getting a trigger to use a parameter, as in the
following simplified example:

CREATE FUNCTION fun_version_table(varchar)
RETURNS opaque
AS 'DECLARE

in_table_name ALIAS FOR $1;
v_counter integer;

BEGIN
SELECT INTO v_counter counter FROM version_table
WHERE table_name = in_table_name;
-- do something in here
RETURN new;
END;'
LANGUAGE 'plpgsql';

CREATE TRIGGER trig_deg_master
AFTER
INSERT OR UPDATE OR DELETE
ON author
FOR EACH ROW
EXECUTE PROCEDURE fun_version_table('degree_master');

Function gets created successfully.But
when I create trigger I get an error:

ERROR:CreateTrigger: function fun_version_table() does not exist

I've created triggers/functions with no parameters and they work fine.

The Postgresql book has some examples of functions with paramters, but
I cannot find anywhere a trigger which calls a function with parameters,

although the users manual indicates that parameters are allowed in the
syntax for CREATE TRIGGER.
 

Regards,
Rahul