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.