Polymorphic "setof record" function?

Hi list,
I have written a function that returns a setof record. The function has
a table name as a parameter and the resulting records have the same
structure as this table. Is there any easy way to specify this when I
call the function? If the table has many columns then it's annoying to
specify all of them.
I need something like:
    select * from myfunc('mytable') as x(like mytable)
or
    select * from myfunc('mytable') as x(mytable%TYPE)

Is there any solution for PostgreSQL 8.2?

Regards,
    Christian

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