HELP! foreign eys & inheritance

The following example worked in previous versions (7.0.2 was the last I 
tested), but not in 7.1 any more:

create table parent (
global_id serial
);

create table child (
anything text
) inherits (parent);

create table foreign (
fk_id int4 references parent(global_id) on update cascade on delete no action
) inherits (parent);

test.sql:83: ERROR:  UNIQUE constraint matching given keys for referenced 
table "child" not found
WHY ???

I would appreciate any help. Our database depends heavily on this.

Horst