Reicevable invoice import from external system

Hi,

I would like to run manually importing invoices from external system.

I make the setup needed in receivables.

I create an invoice in the interface line form but i didn't find the customer field and other information

I check the RA_INTERFACE_LINES_ALL table, and i find that all columns are null.

Did you have any document for this issue ? is there any setup missed ?

Thanks

Mohamed