Int 15 Fn BF04  - Rational Systems DOS/4gw - ???                           [E]

   AX = BF04h
   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
   grabs INT 2Fh and installs handlers for INT 2F/AX=1605h-1607h

See Also: INT 2F/AX=1607h/BX=22C0h