Wondering about this as well. This functionality was included and very simple to use in the old dDo. Can't seem to find any similar features in the new one.
Yeah scaling with floaters so far is not really 100% accurate, i've been fiddling around with it for the past couple of days, will hopefully include it in the update :)
Because PS3 isn't powerful enough to emulate PS2. The early PS3s that ran PS2 games had additional hardware for that purpose that is no longer included.