Max no. of line items reached in FI

Hi Everyone,

My client does billing through a batch job and the program used SDBILL which is assigned to TCode VF04 in Table TSTC.

There are invoices where the line items is fixed at 999.Could somone please tell me how to automatically split invoices whenever the line item exceeds the permissible no. of line items which 999.

Regatrds