Returning sets from functions?

Consider
create function followers(text) returns setof text as
'select id from ids where id > $1 '
language 'sql';

The function seems to work OK:
select followers('h');
does return all indexes after the index 'h'.

On the other hand,
select * from ids where id in (select followers('h'));
produces the message
ERROR: An operand to the '=' operator returns a set of text,
but '=' takes single values, not sets.

Apparently the phrase
select followers('h');
returns a set with members which are 'setof text'. psql has no trouble
displaying all rows, but the parser does ...

So, my question is: can I produce a set in a function so that it
mimicks perfectly the return set of a select query?

I am using PG 6.5.3; is this already solved in the 7.0 beta?

Thanks

Miguel Sofer