Mark you should talk to Doug Petrole at nGenex - (888)696-4369. Not sure but I think that is going to be complicated. Files have to be uploaded to the client's server using FTP. Then move them to the directory structure through the Partner Management Console.
They need to provide a way for the back office data to be accessible to Inaport - either by having the system export it in a format that Inaport can recognize. if they provide a REST API for the back office service then see if Inaport can get the data via rest api request so it can still import to goldmine.