I was just going to say, working for one of the largest destributors in the world, this is still how many large corps buy stuff: by downloading a catalog through FTP and sending the order with XML. I know, shocking but not everyone is Amazon.
Amazon Vendor Central only has support for EDI (at least in the UK) - as in EDIFACT files sent over FTP.
If you want to do business with them you either need to talk that or be comfortable farming out to a 3rd party (I'm 1 day into a project where I'm finding all this out, and the hell of EDI file formats).
