INT 15 - Rational Systems DOS/4GW - INITIALIZE PROTECTED-MODE INTERFACE         
	AX = BF05h
	BX = PSPsee Program Segment Prefix segment of extender
Return: nothing???
Notes:	if BX is not the PSPsee Program Segment Prefix 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 ???