Hmmm, what I missed was the Polarity of the XOUT signal. The PBP manual didn't really go into too much detail, but i found another document on the web that explained it better. It's description goes like this.
Transmit to Power Line—Output a high on this line within 200 μ of Zero Crossing
going high, and hold the line high, to output a one on the power line—that is, to turn on
the 120 kHz oscillator. Use the same timing with a low output to output a zero. The line
should be low if the interface is not to transmit data, since that keeps the oscillator off.
So, 1 turns the 120khz ON, 0 turns it off.

But with the TRIS bit, it works the other way around. 1 = INPUT (OFF),  0 = OUTPUT (ON). Just a little backwards.

I think you're right though, the only way around it is to change the XOUT command itself. Fortunately, it's an easy change if you're willing to tamper with the PBPPIC14.LIB file.

If so, be sure to make a copy of the file before editing, you might want it back the old way later on.

Your mission, should you choose to accept it, is to ...

Open the PBPPIC14.LIB file in the PBP folder, and do a search for XOUT. You should see a section that looks like this
Code:
    ifdef XOUT_USED
  LIST
XOUT2   movlw   2               ; Default to 2 cycles
XOUT    movwf   R2              ; Save number of cycles
        movf    RR1, W          ; Get data port
        movwf   FSR             ; Put it into FSR
        movf    RM1, W          ; Get data bit mask
   ;     call    LOWT            ; Set data to low, output
Comment out the "call     LOWT". We'll handle setting the pin to the correct state manually.

Then scoll down a little bit to xout1loop and change it like this
Code:
xout1loop 
   ;     movf  RM1, W           ; Get data bit mask
   ;     iorwf   INDF, F        ; Set the bit
        comf    RM1, W          ; Get inverted data bit mask
        andwf   INDF, F         ; Clear the bit

        movlw   high 1000       ; Pause 1 ms
        movwf   R0 + 1
        movlw   low 1000
        call    PAUSEUSL

   ;     comf    RM1, W          ; Get inverted data bit mask
   ;     andwf   INDF, F         ; Clear the bit
        movf    RM1, W          ; Get data bit mask
        iorwf   INDF, F         ; Set the bit
It just reverses whether it sets the pin high or low.

Now, to use it ..
Code:
    TRISB.3 = 1          ' start with output OFF
    XOUT TRISB.3,PORTA.0,[house\lightsOff]
Fingers crossed

P.S. Don't blame me if you don't backup the file first.