I think Xps3 switch need 3 wires from the electrical panel. I only have 2 wires!
Even if you don't have a ground/bare (or green) wire in your box, as long as you do have a hot/black and a neutral/white return wire the XPS3 should work.
Do you mean I can use a XPS3 switch and screw the green wire to the bottom of the steel wall switch electrical box where the bare ground is crewed too?
Let me clarify all this some more.
First what we're discussing applies to both the XPS3 and the WS13A. Neither of these appliance switches has any leads on it. They have an 8 connection terminal strip. Two to connect to the line/black. Two to connect to the neutral/white. Two to connect to your load/CFL light fixtures. Two for 3-way control, which you're not using. There is no connection, nor is one needed, for ground/bare (or green).
Presumably you have a black and a white wire coming from your breaker box and and black and white wire going to your CFL fixtures. Both white wires connect to the neutral terminals. The black wire from the breaker connects to a line terminal. The black wire to the CFL fixture connects to a load terminal. Nothing will be connected to the control terminals.