Sorry, but this answer misses the point.
Mac files traditionally have two forks, a data fork and a resource fork. These are presented as a single file to Macintosh clients, even over networks. When uploading, browsers will encode the two files into one stream using an encoding called MacBinary. This happens transparently in the browser.
Other third party upload controls, for example abcupload
, will accept such a MacBinary upload and save the file out (on an NTFS drive) with the resource fork saved in an NTFS alternate stream. This is how Services For Macintosh, a Windows Server service, has been maintaining Mac files for over a decade.
RadUpload does NOT support MacBinary transfer in this way at the current time, from what I can see. This is a fairly damaging limitation, making it impossible to upload Mac Type 1 font files, for example.