Problem using pg_restore with -a option

Hi all,

I'm using PostgreSQL 7.4.7-6sarge2 (debian)

Using the schema below, doing a pg_dump -Fc, delete all data, and a
pg_restore -a, the sequence of inserting data isn't correct issuing an
error.
Could this be a bug?

Notice that on schema, table periodo depends on tipo, but the sequence
is table periodo, then table tipo and after table periodo is changed to
reference tipo.

My schema file:
drop table periodo cascade ;
drop table tipo cascade ;

create table periodo (
"idPeriodo" serial not null,
"idTipo" int4,
designacao varchar(50),
constraint pk_Periodo primary key ("idPeriodo")
) ;

create table tipo (
"idTipo" serial not null,
tipo varchar(5),
designacao varchar(50),
constraint pk_Tipo primary key ("idTipo")
) ;

alter table periodo add constraint fk_tipo
foreign key ("idTipo")
references tipo ("idTipo") ;

My data on tables:
INSERT INTO tipo (tipo,designacao) VALUES ('T','Type');
INSERT INTO periodo ("idTipo",designacao) VALUES (1,'periodo');

Error:
pg_restore: ERROR: insert or update on table "periodo" violates foreign
key constraint "fk_tipo"
DETAIL: Key (idTipo)=(1) is not present in table "tipo".

Best regards,
Luís Sousa