In Utilities billing ofen is necessary to create a manual bill for correcting an automatic bill or for billing special contracts that are hard to bill with a normal billing schema.
For creating a manual bill there is a SAP ISU transaction EA16 which from my point of view is not so user friendly and the user can be confused with all the fields that must be fill.
Another alternative to EA16 transaction would be a custom ABAP report where you can create some templates to create certain types of bill. To create a manual bill from an ABAP program there is a standard function module ISU_S_MANUBILL_CREATE.
Here there is a SDN post where you will find an example of how to fill the imput parameters of this function. Become a SDN member.
I will definetly use this function module in my current project in order to create some kind of bills.
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