PLPGSQL SETOF functions

I am porting some Oracle code to PLPGSQL and am having a problem with functions that return SETOF datatype. In Oracle, the functions I'm porting return a TABLE of TYPE datatype, this TABLE being itself a named type. I am not aware of how to do this in PLPGSQL.

Consider a function with header:
CREATE OR REPLACE FUNCTION dates_pkg.getbusinessdays(pstartdate timestamp with time zone, penddate timestamp with time zone) RETURNS SETOF timestamp with time zone AS

I can easily call this function in SQL like so:
select * from dates_pkg.getbusinessdays( now(), now() + INTERVAL '7' day ) as business_day;

However, I can't figure out how to call this function from another plpgsql function. Any hints?

~Dave Greco