Kindlet File I/O permissions

Hi, I'm developing a kindlet and I would like to access the Kindle root file system. When I try to read a file I get a Java I/O persmission error in the "crash.log" file. I thought it was due to the fact that the cvm doesn't have root permissions so I try to access the user storage ("/mnt/us") but I got the same crash. Is it possible to access the file system from within a kindlet?
I read about a patch for root permissions when I started looking for informations about kindlet but I can't find it anymore.