pg_dump problem

PgSQL 7.0.2

I used pg_dump to dump the schema of a db. I created table part_presencial
with this command

create table part_presencial(
login char(15) not null,
id_curso_polo int4 not null,
data_encontro date not null,
nota numeric(2,2) null,
foreign key(login,id_curso_polo) references matricula,
foreign key(id_curso_polo,data_encontro) references presencial,
primary key(login,id_curso_polo,data_encontro));

But pg_dump gives me this:

CREATE TABLE "part_presencial" (
"login" char(15) NOT NULL,
"id_curso_polo" int4 NOT NULL,
"data_encontro" date NOT NULL,
"nota" numeric(2,2),
PRIMARY KEY ("login", "id_curso_polo", "data_encontro")
);

Why doesn't pg_dump give me foreign keys constraints? It happens to all the
tables with foreign keys.

-----
Paulo Roberto Siqueira
paulo(dot)siqueira(at)usa(dot)net
Database Administrator
Goiania - GO - Brazil