We need an osCommerce module (contribution) for performing a credit check when a customer opts to pay by invoice.
This will be done through an inteface provided by Deltavista ([login to view URL],ge/).
The enclosed Gateway document (in english) should be enough for a skilled programmer to make such a module (according to Deltavista).
The technology for this interface is based on SOAP.
You will get access to a test account once you accept this request.