inheritance and foreign key

Hello,

We have the following schema :
create table A (id_A integer primary key,b_A integer);
create table B (a_B integer) inherits A;
create table C (id_C integer primary key, b_C integer);
create table D (id1 integer references A (id_A),
id2 integer references C (id_C),
primary key(id1, id2));

Problem occurs when we want to insert a tuple into D
that references a B's tuple. Our idea is :
create table D (id1 integer references A* (id_A),
id2 integer references C (id_C),
primary key(id1, id2));
which is not allowed by postgres.

Does anyone has experimented such problem?

Thanks