The 4-button remote for the RS series is not compatible with your system. The good news is that the one you need is, generally, still available. You need a 4-button remote for the Ji series Jandy. Not particulary cheap.

Pop the existing button from it's housing (it is just "pressed" in), cut the wiring off the back, attach the new wiring very securely to the old and, using the old wire at the control panel, pull it through the conduit. It is better to have someone at the spa feed the wire, because you cannot pull it if there is a kink in the wire. If you try you will either break the wire internally or pull the splice apart. Bad either way, worse if you break the new wire.