I need to replace the old (20 yrs) Delta Faucet shower tub set up... Are their any new Delta Faucet Handles that I can install with the current valve so I don't have to remove the entire 1 piece shower insert? I took what I could apart and I am down to what they now call the "cartridge" but mine doesn't seem to have any removable "cartridge" just the ball shaped handle stem which inserts into a socket with three holes in it... Somebody please help.