Custom field - Invoice header

Hi everyone,

I have a requirement to add a custom field in the CREATE INVOICE screen in the INVOICE HEADER under the section "Unplanned Delivery Costs".

Can anyone please let me know what are the steps for adding the custom field in general to any SNC screen which is WEB DYNPRO based?

I already referred the below link which talks about screen enhancements using UI framework but since the INVOICE CREATE screen is web dynpro based the steps in the below link cannot be used.

http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/208895d6-fef1-2c10-4086-fee29a29c29c?overridelayout=t…

Any inputs are highly appreciated.

Thanks.