The full story has still not been told: The Custom Load/Save button only loads SINGLE custom styles into individual slots in the custom section. Full custom loads (20 styles at once) are saved and loaded under the SD button along with Composers, Songs, Sounds and others which can be selectively chosen to be saved or loaded. If no SINGLE customs have been saved on the card then it is no wonder that menu shows no contents.

Single customs are saved in an entirely different folder to the TfldXXX folders, namely a Custom folder inside the KN7000 folder within the card structure. This folder can simply be dragged and dropped between SD cards without affecting the menu view because it does not depend on any index inf file. Likewise any single custom *.cst files can just be dropped into this folder without any special pc program like SDExplorer to then show up in that menu.