Hi Jade,
I thought this was put back in 4.6. The problem is that the download page must query the filename on the database. Much like how it does when you are viewing the file on the version level page. On the folder level page it must query that too. And pass that on www/download/index.vuh
So the link on href will be [file-storage mount point]/download/[file name]?version_id=xxx The browser will get [file name].
I have worked on this but the code is pre 4.5 beta and when I reported this about more than a year ago in the bboard it was said that it will be done, I guess it wasn't.