Uploaded file stored in browsers memory

Hi,

I've noticed that any file that I'm trying to upload using SWFupload first gets loaded in to my browsers memory. Is this the expected behaviour? Is there anything I can do to make it stream from the disk instead because obviously this will make uploads of really large files much less intensive on the client than with the current setup?

My setup is
- SWFupload 2.1.0 with flash 9 component
- Firefox 2 or Safari 2 running on OS X 10.5.2 and with whatever flash version 9 that comes with it