How to load External Payments into Oracle and Reconcile With Bank Statement

Summary:

My client use's a ABC system to issue checks to supplier. Later, ABC sends payment details to Oracle, and we need to load these into Oracle and generate Positive Pay files for the bank and we have to reconcile the same. Client have no invoice details in Oracle for these payments.

We are thinking of using one time payment to load dummy invoices and get it paid. But how can get the Check number from external system and the same number should be used in Positive Pay, so that we reconcile everyday. Any body had similar requirement in the past.