Parsing '\x00' -- appears to be the only thing preventing parsing binary data

I am trying to parse binary files and obviously need to write rules that include the 8-bit value 0x00 — flex appears to allow me to obtain an 8-bit scanner using the -8 option. I seem to be able to use ‘\x01’ to ‘\xFF’ for individual terminal symbols in Bison rules. Unfortunately, ‘\x00’ is used to denote end of input. Looking at the output tables, there appears to be no real reason to do this (other than convenience) and I am wondering if anyone has a workaround? 
Thanks !
Steve