Maestro,
You still have not answered the question completely:

Are you running Solaris on a PC or on a Sun system?

From your comments I am guessing it is a Sun system in which case there is no PXE. As I explained earlier it uses bootp from NVRAM (similar to BIOS but not quite the same). I suggest you go to docs.sun.com and read about NVRAM and OpenBoot. The 'eeprom' command will let you interface NVRAM from the OS, but again there is no PXE and NVRAM is not BIOS!