PA AR invoices

Hi,

Our PA module is integrated with AR module wherein we send PA draft invoices to AR and final invoice is generated in AR.

We have an upcoming project where we need to enable PA for a country but AR and AP is already live.

The challenge is we have some open and close invoices which needs to be converted in PA and i am looking for suggestions how should be convert data in PA considering these invoices are issued and accounted in AR.

Thanks!!