INT 2F - Novell NetWare - DOS Requester v1.03+ - GET VLM CallA ADDRESS          
	AX = 7A20h
	BX = 0001h
Return: AX = 0000h if request was handled
	    ES:BX -> CallA entry point (see #02893)
SeeAlso: AX=7A20h/BX=0000h


(Table 02893)
Call VLM CallA entry point with:
	AX = function
	    0000h submit
	    0001h cancel (not implemented)
	ES:DI -> Overlay Asynchronous Control Block structure (see #02894)
Return: DI, DS, ES preserved; all other registers may be destroyed
	interrupts disabled
Desc:	asychronously call the specified VLM and then return to caller, which
	  might be another VLM


Format of Overlay Asynchronous Control Block (OACB):
Offset	Size	Description	(Table 02894)
 00h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	link to next OACB, 0000h:0000h if last (filled by VLM.EXE)
 04h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	callback address or 0000h:0000h
 08h	BYTE	InUse flag (00h if complete) (set by VLM.EXE)
 09h	BYTE	flag, reserved for VLM use
 0Ah	WORD	destination VLM
 0Ch	WORD	destination function
 0Eh	WORD	temporary storage for VLM.EXE
 10h  6 BYTEs	reserved
 16h  6 DWORDs	EAX,EBX,ECX,EDX,ESI,EDI
 2Eh  4 WORDs	DS,ES,FS,GS (FS and GS not used)