Function parameters change when update to 8.3

I have function in PostgreSQL 8.2
CREATE OR REPLACE FUNCTION post_ctpxd(ud_stt_rec)
  RETURNS void AS
$BODY$DECLARE
    ...
BEGIN
    ....
END
$BODY$
  LANGUAGE 'plpgsql' VOLATILE;

My domain in 8.2
CREATE DOMAIN ud_stt_rec
  AS character(20)
  DEFAULT ''::bpchar
  NOT NULL;

But when I dump database and restore to 8.3 this function change to

CREATE OR REPLACE FUNCTION post_ctpt1(ud_stt_rec(24))
  RETURNS void AS
$BODY$DECLARE
    ...
BEGIN
    ...
END
$BODY$
  LANGUAGE 'plpgsql' VOLATILE
 COST 100;

My domain in 8.3
CREATE DOMAIN ud_stt_rec
  AS character(20)
  DEFAULT ''::bpchar;

So when I run script CREATE OR REPLACE FUNCTION post_ctpt1
it have error

ERROR:  type modifier is not allowed for type "ud_stt_rec"

********** Error **********

ERROR: type modifier is not allowed for type "ud_stt_rec"
SQL state: 42601

Please help me. Thank you very much.

Tuan Hoang Anh
hatuan05@gmail.com