does prepareThreshold work? forced to use old driver

hi!

I've been having some serious performance issues with
postgresql8.2/hibernate/jdbc due to postgres reusing bad cached query
plans. It doesn't look at the parameter values and therefore does not
use any partial indexes.

After trying to set prepareThreshold=0 in the connection string which
didnt work, even modifying the jdbc driver and forcing it to 0 and not
working I realized that it must be being ignored. After giving up
pretty much I tried a much older driver which doesn't use server
prepared statements at all the problem has gone away and it is once
again using the partial indexes. How can I get this to work properly
on the new jdbc driver? I don't really like having to use a 2 year old
driver to get good performance as you can imagine :)

Could someone point me to a jdbc src file where I could just disable
server-side prepared statements entirely?

--
thanks, G