We have a requirement in our project wherein, if the Forwarding Agent is not maintained in SO, forwarding agent should be added to Delivery Header (partner Function under partner tab) as soon as you click on Deliver Option(under Sales Document menu in VA02/VA03) i.e. Before it is saved.
I have implemented a logic inside USEREXIT_SAVE_DOCUMENT_PREPARE, but it gets triggered after clicking on Save Button. But according to user, the SP partner function should be added to Delivery header as soon as he clicks on Deliver Option(under Sales Document menu in VA02/VA03).
Please suggest if there is any BADi ot user-exit where i can put my logic.