Trying to implement Integration Broker Web Service for Inbound invoices from Staples

We are currently trying to setup an Integration Broker solution to allow inbound invoices from Staples, into our PeopleSoft FSCM application.  They have told us that we can either handle the transfer via FTP or HTTPS.  I would rather go for the HTTPS route. I was not clear on whether they would be giving us a URL (for us to pull invoices down) or if we have to give them a URL (to push invoices to us).  After a conference call to them yesterday, it appears they want a URL from us. So I poured over PeopleBooks, eKit, Google Searches, and