Is it possible to import partially paid invoices in R12?

I am currently trying to implement a solution for our users in Payables which allows them to import invoices which have been processed externally. This will be done by transferring the invoices into the interface tables and then importing them using the Payables Open Interface Import. The outstanding issue is that there will be quite large volumes of these invoices on a regular basis and many of them will be paid or partially paid. I understand there is no way to import payments which have been made but I was hoping to generate payments for these invoices on the system