BUG #3423: cache on temporary tables in plpgsql

The following bug has been logged online:

Bug reference:      3423
Logged by:          vituko
Email address:      vituko@gmail.com
PostgreSQL version: 7.4
Operating system:   debian sarge
Description:        cache on temporary tables in plpgsql
Details:

"relation with OID ##### does not exist" errors when accessing temporary
tables in PL/PgSQL functions

related :
bug : 2005-12/msg00207.php :
possible solution :
faq : 4.19
but :

I'm working on 7.4 and execute command cannot return any value (execute into
is not implemented). So I cannot see any alternative. Any suggestions?

I have a loop "for record in select...", for each record, I get a table name
and then I do an 'execute query', creating a temporary table and from this
temporary table I need a field value.

What can I do?

Thank you very much.