Using T-Code RBT_ENH_VB7, what is mandatory?

Hi!

I was writing a work instruction for our end users on how to use the RBT_ENH_VB7 transaction code. When executing I'm wondering which fields are mandatory and how the behavior of this field relates to the setting in the rebate. As I know based on the experience of running the VBOF (which is easier to validate due to the Test option), rebate agreement or customer are mandatory.

Is there any background document on the remaining fields in the Settlement of extended rebates screen?

Thanks for the help!