Billing split to avoid 999 items issue in FI doc

Below link is useful:
http://scn.sap.com/thread/1519325

In IMG setting, you can restrict the number of line item that should flow in billing.

 

Go to IMG => SD => Billing => Billing Docs => Country specific features.
You also require to change copy routine for split (refer routine 006) to consider the limit given above.


Also, While creating invoice via VF01 you can go to selection list and choose the lines which you want to invoice.

Setup G/L account in PO based on Material group

To setup G/L account in PO based on Material group (used for Non-stock - NO material)
OMSK - Create valuation class

Assign valuation class to Material group:
SPRO -> MM -> Purchasing -> Material Master -> Entry Aids for Items Without a Material Master 

Assign G/L account to Valuation class
OBYC -> GBB -> (CCGR + VBR + <new val class> = G/L accnt)