Foreign Key on Inheriting Table?

There's some mention in the (old!) documentation that constraints such as foreign keys won't include data from
inheritingtables, eg: 

  CREATE TABLE foo (
     id SERIAL PRIMARY KEY
  );

  CREATE TABLE bar (
     attribute integer NOT NULL
  ) INHERITS (foo);

  CREATE TABLE bar_widgets (
     bar integer CONSTRAINT bar_exists REFERENCES foo (id)
  );


Now if you populate bar, you can't put anything in bar_widgets, because the foreign key constraint is not satisfied.

Similarly, if you want to have self-referencing items (eg: two points link together):

  CREATE TABLE anomalies (
     id integer PRIMARY KEY,
     x integer NOT NULL,
     y integer NOT NULL
  );

  CREATE TABLE wormholes (
     other_end integer CONSTRAINT has_end REFERENCES wormholes (id)
  ) INHERITS (anomalies);


This won't work because the wormholes tables doesn't actually have the id column (the anomalies table has it).

This won't work either:

  CREATE TABLE wormhole_tubes (
     left_end integer CONSTRAINT left_exists REFERENCES wormholes (id),
     right_end integer CONSTRAINT right_exists REFERENCES wormholes (id)
  );


While I could adjust my code to treat wormholes separately to all other anomalies, I was hoping to take advantage of
theobject-relational features of PostgreSQL to make my work a little easier. 

Does anyone know whether I'm just doing something wrong, or is the old documentation still correct?

Thanks
Alex Satrapa