We're migrating a Windows based FTP solution to Linux that extensively passes FTP through to UNC directories on remote servers.
Serv-U on windows supports UNC pass through of virtual directories, however Serv-U on Linux doesn't while all documentation says it does.
Serv-U could mount UNC paths at access with samba (passing through the NT auth to the end share) and unmount them when the user sessions disconnect.
This is actually a big limiting factor, we may end up moving to vsftpd at some point as Serv-U really doesn't offer a way to do this.
