def _read_Btw_item(data,control):
	"""Read a Btw item from the start of DATA.

	Returns a tuple containing the item read (as a string) and what is
	left of DATA.

	The order of octets is:

		"B"	MSOF (most  significant octet first)
		"b"	LSOF (least significant octet first)

	(as discussed in 6.4.3.3 h))

	In the case of a "b" format, we reorder the octets into MSOF
	"""

	# We have a Btw or btw item

	# If it is complex, it is double the size

	if control.control[1] == "5":
		size = control.size * 2
	else:
		size = control.size

	# First off, we can extract the relevant number of octets

	item = data[:size]
	data = data[size:]

	# And now interpret them

	if control.control[0] == "b":
		# LSOF form - reverse it

		thing = ""
		for count in range(control.size-1,-1,-1):
			thing = thing + item[count]

		item = thing

	# So we've now got the MSOF form, regardless of the format

	# As of yet, we don't do anything with it...

	return (item,data)