There are some 120 to 220 volt modifications for X10 modules on this web site.
http://www.idobartana.com/hakb/index.htmMost of the modules use a line driven type power supply. Using an AC rated capacitor to limit the current into the power supply. Along with a few filter caps, diodes and Zener Diodes.
On those. The capacitors, resistors and MOVs are changed.
Many of our US models have the hot Line input as the common power supply reference.
The CM15A has a power transformer. So changing it to 220 would need a new transformer and coupling capacitor for the power line signals to the power line receiver and transmitter.
The CM15Pro being European also has a completely different X10 RF 433.92MHz frequency from our 310MHz.