It depends how you define your LampLinc for ActiveHome Pro.
If you define your LampLinc as an LM14A (by dragging the LM14A icon into the room), AHP will use the Extended Code commands which the LampLinc does not support, so the command won't be recognized. However if you define the LampLinc as a standard X10 Lamp Module like the LM465, then AHP will use the standard X10 Dim and Bright commands which the LampLinc does support.  But you will find that the visible brightness of a lamp connected to a LampLinc will be different than that of a lamp connected to a LM465 for the same percentage brightness, so you'll have to adjust the percentage.
There will be some other differences, e.g., an LM465 in the dimmed state will not change if it receives an AllLightsOn command, whereas a LampLinc will go to full brightness. So the state of the lamp as displayed by AHP will be incorrect. Similarly, a LampLinc can be manually configured to resume its previous brightness level when turned On after having been turned Off. So a LampLinc thus configured will be displayed in AHP as fully On whereas the actual lamp will be dimmed.
Ah-ha! Now I fully understand.
Thanks much Charles in your explanation regarding this (you earned a "helpful" link click by me). All in all I hope that X10 works out their LM14A stock soon.