PaoloM wrote:

Unfortunately, alternate data streams are lost when you move the file to a non-NTFS system, with no warning or anything. The user experience in that case is very jarring and unexpected...

I am looking at possible options to solve exactly this problem

That was why I think WinFS was such a big part of Longhorn's original vision, allowing the OS to crack open files and put meta data inside them when they left the sanctity of the "Store".