It's possible and Work!!
Don't put the information in the remote upload box BUT put it in Filesonic link and Don't use the your email USE your user name
ex.
http://www.filesonic.com/file/1234/yourfile.rar <-- you can get it from share button
Do like this
http://yourFSNusername:yourFSNpassword@www.filesonic.com/file/1234/yourfile.rar
Now Wupload is sooooo hot, that means you may need to wait for upload queue for a long time.
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