Add invoice distribution lines with ap interface?

Hi,

We need to add distribution lines to an invoice in payables from a database that's not Oracle Financials.

Now we are on 11.5.10.2 and we are inserting invoices in AP from an external database with the Payables Open Interface, this database will generate more distribution lines (only distributions, not lines, of course the sum of this lines will be zero) and we don't know how to insert them in AP tables.

Any idea?

Thanks and regards

María Salgado