Yup, there's info somewhere in this forum on that - I think I posted it, but can't find it now.

Here's a link from the FCO airport website: http://www.adr.it/documents/10157/10...8-20d3c39e5b9b

It's a PDF in multiple languages.

The short answer, though, is that agencies like Global Blue work because they have more convenient refund locations. I'm guessing they're slightly more lax on other procedure as well, but who knows. At least at FCO, getting the direct refund isn't too difficult. You go to customs before checking in.