The PBP commands are for use with a TW523 or equivalent. They are rather limiting with no support for the newer extended commands.

Anand Dhuru has posted here a few times about designing his own send/receive circuits (for 230V). And there was an exchange between Anand and Darrell Taylor about modifying the X10 Out command for direct output of 120kHz bursts, eliminating the need for a TW523.

There was a recent thread where I listed a few powerline modem chips which might be applicable (although most now available are FSK) and Anand referred to a Nuts & Volts article (Building the X-Lock) from September 2001 that has a schematic for a two-way interface using simple components.