To allow the user to identify a file to upload to the server
you must use FileReference. If you have data in memory (like XML or
arrays) you can use HTTPService and send the data using the POST
method on HTTPService.
There is no way to automatically read files from the user's
local machine. That would be a serious security threat. You can
imagine what could happen if you could write a Flash app that very
innocently ask for a file and then just went and uploaded all of
the data files in a user's directory without their permission.
So, no, you cannot automatically upload files using
FileReference or HTTPService or anything else.