INT 15 - Rational Systems DOS/4GW - ???                                         
	AX = BF06h
	BX = PSPsee Program Segment Prefix segment of extender
	???
Return: ???
Note:	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
SeeAlso: AX=BF03h