I don't know if PBP has a DEFINE that goes that high, but in any case you can always directly set the SPBRG register. The exact setting depends on your oscillator frequency, but if you are running at 20Mhz, you can set
SPBRG = 32 to give you 38.4Kbaud.
You will have to consult the datasheet if you are running at a different frequency.