i have the same issue, i cant see any reason for the sharecenter to be hiding these folders, this adds severeal unnecessary steps from download to usable file on the nas.
the files i usualy download are compressed, and i want to continue seeding them, so..
instead of: download files, unpack files, use files.
i get: download files, log into nas, go into web file server, copy files, unpack files, delete files, use files.