Default Document Type Abbrevation:
------ Sales --------
1) Sales Order = SO
2) Delivery Order = DO
3) Sales Invoice = IN
4) Cash Sales Invoice = CS * added 1/7/2012
5) Picking Order = PK
6) Shipment = SP
7) Sales Return = SR
8) Return Receipt = RR
9) Sales Credit Note = CN
10) Sales Debit Note = DN
11) Sales Collection (Receipt) = RE

------ Purchase --------
12) Purchase Order = PO
13) Goods Receipt = GR
14) Purchase Invoice = PI
15) Cash Purchase Invoice = CP * added 1/7/2012
16) Purchase Return = PR
17) Purchase Credit Note = PC
18) Purchase Debit Note = PD, Return Delivery = RD
19) Purchase Payment = PM

------ Stock -------- (Inventory = I)
20) Stock Adjustment = IA
21) Stock Transfer = IT
22) Stock Issue= IS
23) Stock Receive= IR
24) Item Assembly= IB
25) Stock Count= IC

------ Historical Transaction (For K/O Only) ---------
XI = History Sales Invoice
XC = History C/N
XD = History D/N
XP = History Sales Payment

YI = History Purchase Invoice
YC = History C/N
YD = History D/N
YP = History Purchase Payment


Delivery Order
Draft, Status = 0
WIP, Status = 3

Posting Delivery Order
	if Status = 0, user can confirm, and will post to stock

Invoice
Draft, Status = 0, generated from Sales Order
WIP, Status = 3, generated from Delivery Order
	WIP, the user can change the item price, but can not change other fields, because Delivery Order already post to stock
	user can delete the invoice, and restore to Delivery Order status 3
Complete, Status = 4
	after user confirm the invoice (posting the invoice)

Posting Invoice
	if Status = 0, will post to stock and accounting
	if Status = 3, will just post to accounting, because Delivery Order already post to stock
	
Posting Invoice WIP (status == 3)
	it will update some fields in stk_trans, like account_id, net_amt, and so on, and change doc_type to 'IN' from 'DO' and update the doc_code to inv_code