function cache effect still happening?

Hi everyone, a few months ago I was still using Postgresql 8.2 and had the
problem described here:
http://www.postgresql.org/docs/faqs.FAQ.html#item4.19 , that time I solved
it using EXECUTE for all sentences accessing temporary tables. Right now I'm
using 8.3, the scenario is a little different but the problem is the same.
I have many schemas with the same structure (tables, views and one trigger),
and two functions in the public schema which insert and delete data from
them, the INSERT and DELETE sentences are hard-coded. Every schema
represents a store from the same company.

The idea is that just by changing the search_path value to something like
"schema1,public", it's possible to execute the functions and to process data
for any schema (one at a time). But the problem is here: through the client
app, a user invokes one of these functions on a given schema (schema1), then
requests a "store change", actually setting the search_path to use another
schema (schema2) and again, executes any of the functions that access the
schema tables, BUT the function seems to be still linked to the first
schema, so new records are added to the wrong schema and delete operations
don't find the right record. EXECUTE will save the day again, but I'd like
to know if this is considered a known bug even when it was apparently fixed.

Thanks.