nvidia sheld external hard drive

having issues with saving movies to my external drives, i plug them in and can see them in the sheild settings, but i have too set them up as internal storage for kodi to save to them, I have both a 2tb hard drive and 128gb micro sd card conected to my sheild and both need to be set up as internal storage for kodi to save to the directories i set up for them. is there any way to get kodi to save to them as external storage?