So I heard from Alexandre at UVI on this. For anyone interested, here’s what he said:

“If you want to save your work as a monolithic UFS file, you will have to contact our Partner Team and draw up a dedicated contract that implies licensing fees as UFS (which stands UVI File System) is a proprietary format.”

Here’s link to the inquiry screen.

There’s a fee involved as well.

I can understand their wanting to ensure quality and protecting proprietary formats.