tables referenced from insert...returning

Hi,

What are the rules about what tables/views can be referenced from the
RETURNING clause of an INSERT?

I am particularly puzzled by the following.  Given these definitions:

CREATE TABLE test (id serial primary key, name varchar);
CREATE VIEW tv AS SELECT * FROM test;

This works:

CREATE RULE _update AS ON UPDATE TO tv DO INSTEAD
  UPDATE test SET name = NEW.name WHERE id = OLD.id RETURNING NEW.*;

But this does not:

CREATE RULE _insert AS ON INSERT TO tv DO INSTEAD
  INSERT INTO test (name) VALUES (NEW.name) RETURNING NEW.*;

It gives

ERROR:  invalid reference to FROM-clause entry for table "*NEW*"
LINE 2:   INSERT INTO test (name) VALUES (NEW.name) RETURNING NEW.*;
                                                              ^
HINT:  There is an entry for table "*NEW*", but it cannot be
referenced from this part of the query.

Why is there a difference?

Thanks!
Mike