Smarthome is a totally different system right?
There is INSTEON system, which is conceptionally similar to X10, but yet different. However, SmartHome's
xxxxLinc modules are usually compatile with both INSTEON and X10.
I looked at the LampLinc module, 2456D3, you mentioned, and while it can be manually programmed to do some interesting things, including a slow power-on ramp for up to 9 minutes. However, it doesn't appear to be programmable by direct X10 extended commands.