If it is strictly TMCC, you don't need even need the PM-1. The center slot of the PH-1 connector goes to the center rail lockon clip 1, the outer slot(bottom, not the blank slot at the pointed end) goes to common outside rails clip 2. The Command Base terminal connects to any convenient outside rail connection on the TMCC loop. You only need to be sure to power up the Command Base before the track power so the TMCC loco sees the command signal.
Reading through your original post, it looks like everything was working fine with the PM-1, when configured that way, just flip the PM-1 switch from conv to cmd, connect the powered Command Base to "U", and you are running TMCC.
