Only X10 knows if the two pin appliance modules are also CFL friendly.
I know by design the same PCB fits both cases; but do no know if the new boards are in the two pin ones. Also the sales site does not say they are.
From what I know about electrical circuits and X10 (this actually applies to any timer that doesn't have a battery in it), a "two-wire" timer (or X10 switch in this case) will never be compatible with CFLs, unless they are engineered to work with such a device.
By definition, a "two-wire" switch or timer gets powered by running a small amount of current through the load (in this case, the light) to complete the circuit. This works with an incandescent bulb, but doesn't work with a flourescent, as you can't pass a "small amount" of current through one.
The timers that are designed to work with CFLs either have a battery in them (and don't try to run the timer itself off the AC), or have a Neutral (white) wire, and use that to complete the circuit.