Help > Arduino and VDIP1

Hello,
I'm working at a project using Arduino mega 2560 and a VDIP1 set on UART comunications.
I managed to hook up everything and I managed to write into a file on a USB flash drive through the VDIP1.
The problem is that I would like to create a file from 0 like a bit by bit copy from the computer [Later I'm aiming to implement an encryption on arduino for the file].
Is someone able to explain how can I create a file from 0 because I was able just to create and write into a .TXT file.

PS.: VDIP1 docs: http://www.ftdichip.com/Firmware/Precompiled/UM_VinculumFirmware_V205.pdf