As pointed out by someone else, you can receive stuff transmitted
with two stop bits on a serial port set to do one.  The PIC can send 9
data bits.  The ninth bit can be used for parity or set for marking
parity, which is equivalent to an extra stop bit.
        Another trick I used where I had to send a break between a couple
characters (which was done by putting a resistor in series with the
serial tx line out of the pic, then tying it to another port line that
was either tri-stated (letting data go through) or programmed low,
forcing a break).  The trick was to get the break to not land on top of
characters.   Double buffering of the serial port made it difficult to
figure out when one character was finished transmitting and I could
assert the break.  This was using the serial port transmit interrupt,
which generates an interrupt when the transmit buffer (not shift
register) is empty.  What I ended up doing was ignoring the transmit
interrupt and instead used a timer interrupt.  Each time the timer
interrupt is called, it dumps a character into the serial port.  A VERY
short time later, it starts clocking out.  Since the stuff was not
buffered by the serial port (it started transmitting almost immediately),
I was able to assume when the next timer interrupt was called that the
previous byte had been sent and it was ok to set the break.  So... back
to your problem, you can do something similar (use the timer interrupt
instead of the transmit interrupt) and set the timer for the time
required to transmit the byte plus the start bit plus the two stop bits.
The transmitter will sit idle waiting for the next interrupt to load it.
The idle transmitter is in the mark condition, just like a stop bit!


Harold