[Pljava-dev] cannot set the classpath to a specific jar to get an external connection

Hi all,
not sure if what I'd like to do is possible, but I'd like to use JDBC within a
pl/java function to extract data from another database (something similar to
dbilink). However if I try to change the connection to another URL rather that
"jdbc:default:connection" I got an error saying there is no suitable driver,
so I tried to add explicitly the postgresql jar to the schema, but the
following fails:

select sqlj.set_classpath('public',
'/java/jars/postgresql-8.4-701.jdbc4.jar');
ERROR: java.sql.SQLException: No such jar:
/java/jars/postgresql-8.4-701.jdbc4.jar

So my questions are:
1) what am I missing in setting the classpath?
2) is it possible to open a connection to another database cluster?

Thanks,
Luca