Format of APPC/PC "Transfer Message Data" control block:
Offset	Size	Description	)
 00h 12 BYTEs	reserved
 0Ch	WORD	1C00h (verb "Transfer Message Data")
 0Eh	BYTE	data type
		00h user defined
		01h NMVT
		02h alert subvectors
		03h PDSTATS subvectors
 0Fh  5 BYTEs	00h
 14h	DWORD	(big-endian) return code (see #03668)
 18h 12 BYTEs	00h
 24h	BYTE	flags (see #03704)
 25h	BYTE	00h
 26h	WORD	length of data
 28h  N BYTEs	data