Photoshop Plugin Panel creation - accessing the file system

I am trying to write a plugin that can export content from photoshop .

My problem is setting the export directory from the Panel UI I am creating with Flex.

So far I was able to find some working code for

var fileRef:FileReference = new FileReference();

fileRef.browse();

But my goal is selecting a file or a directory and it seems to me that FileReference() is only used to upload a file.

Then I also found some documentation for the File class that allow a similar functionality but Flex complains that the Type File was not found and I cannot get enough documentation to implement this secondary file browser in my photoshop plugin.

Am I missing something?