How to create new assets in PeopleSoft AM from non-PeopleSoft PO Receipts and Invoices

We plan to create purchase orders, perform receiving ( with serial and tag numbers), and process invoices in a system external to PeopleSoft.  Invoices will be sent to PeopleSoft to load as vouchers to create payments.

How can new assets be created in PeopleSoft that include Serial Ids, Tag numbers, Item Descriptions, and other data required to create an asset?  These would be new assets being created, not a conversion of existing asset ids currently in another system.

The delivered RECVPUSH will not be run (since there are no PS Receipts) and if only INTFAPAM is run, then there is no option to mark the voucher line as serialize if required; users would not want to manually unitize before AMIF1000 transaction load.