PLEASE help with foreign key and inheritance problem

I stated this before, but I did not get a helpful answer. I might have
misunderstood tghe documentation on foreign keys:

create table global(id serial);
create table child(anything text) inherits(global);
insert into child(anything) values ('test);

Now, a select * from child shows
id anything
-------------
1 test

So far, so good.

create table dependend(globid int4 references child(id) on update cascade on
delete cascade);

gives me an error:
CREATE TABLE will create implicit trigger(s) for FOREIGN KEY check(s)
ERROR: UNIQUE constraint matching given keys for referenced table "child"
not found

Once again, _why_ is this? What would inheritance be good for if I can't use
it this way? Bad enough that inheritance of triggers or constraints doesn't
work, but a simple refernce to a attribute should be possible, shouldn't it?

If there is a good reason not to allow it, I would like to know. If not, I
would be willing to help out implementing it, if somebody points me into the
right direction in the code (or documentation)

Horst