aliases and set of record

I'd like to use default param so I build up an alias of BasketItems
create or replace function BasketItems(
_BasketID bigint, _Split boolean, out _ItemID int, out _qty
real )

as...

create or replace function BasketItems(
_BasketID bigint, out _ItemID int, out _qty real
)
returns setof record as
$$
declare
_row record;
begin
for _row in
select _ItemID as __ItemID, _qty as __qty from
BasketItems(_BasketID,null)
loop
_ItemID:=_row.__ItemID;
_qty:=_row.__qty;
return next;
end loop;
return;
end;
$$ language plpgsql;

This return 2 empty records _qty and _ItemID are empty
select * from BasketItems(2);

this returns what's expected:
select _ItemID as __ItemID, _qty as __qty from BasketItems(2,null);

What's wrong?

Any way to fix it keeping the names of the returned columns
consistent?

--
Ivan Sergio Borgonovo
http://www.webthatworks.it