Int 15 Fn BF05  - Rational Systems Dos/4gw - Initialize Protected-mode In  [E]

   AX = BF05h
   BX = PSP segment of extender

Return: nothing???

Notes: if BX is not the PSP segment of the extender, it passes the call down
     the INT 15 chain; this allows nested instances of the extender
   calls INT 67/AX=DE01h if ???