Hi,
Step1:
maintain standard sales order with delivery related billing
service order with order related billing
Step2:
Make sure that
for the line item 10 -Maintain Billing relevance - A-Order related Billing Document
for line item 20 Maintain Billing relevance - B-Relevant for Order related Billing -Status according Quantity
Step3:
maintain necessary copy controls-VTFL & VTFA(alredy Mr.Venu suggested) for
Z4LF to Billing Document & Z4LS to Billing Document
follow remain things as per Mr.Venu suggestion.
Regards,
Krishna.