Hello mvg,
access to the file system is a target specific aspect. Therefore there is no common interface to any file systems in Embedded Wizard. Instead you can integrate your particular files system. See the section Integrating with the device for description how target specific code (native code) is executed from Embedded Wizard platform independent code. In the native code you can invoke e.g. C lib function to open files, read file contents, etc.
Does it answer your question?
Best regards
Paul Banach