SELECT with Function

Hello,

This is my first message to pgsql-novice.

I create plpgsql function "myfunc(integer)" thats returns of type
record with values from table X (the function decides what record must
be select). The parameter is an keyprod existing in table X and in
table A.

It run well sending in psql:
SELECT * FROM myfunc( 10006530 ) as (vret1 numeric, vret2 numeric);

The problem is:
I need return data from table A (this have column 'keyprod'). This
value must be passed as parameter to myfunc(). The result must be a
union of columns selected from table A and result of myfunc().

How to create this query? It's possible?

Thanks

Paulo Nievierowski

PS: Excuses my poor english.