Hi,
I would guess there are no payment details defined in a tab 'Payment details' in a deal itself - please verify it with a SAP trans. FTR_EDIT.
in order to default payment details, make sure these are defined on Business partner level -> SAP trans. BP -> choose a respective Business partner -> select a button 'Company code' -> select a tab 'SI: Payment details' -> see if payment details are defined in a particuar currency and also if a specific Product type is assigned to these payment details.
hope this will help you.
Kind regards,
Renatas
