I can't retrieve a scrollable ResultSet from CallableStatement

Hi,

I'm using posgresql 7.4 and I'm trying to receive a scrollable and updatable ResulSet with jdbc. But when I when I check the type of the ResultSet I've retrieved its always FORWARD_ONLY. I use jdbc3 driver.

the code:

CallableStatement call = con.prepareCall("{ ? = call getRefcursor () }", ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);

call.registerOutParameter(1, Types.OTHER);
call.execute();
ResultSet rs = (ResultSet) call.getObject(1);

rs.last(); //this line throws the Exception

What do I need to do, to make it work!