@odie
I managed to solve this (partially). I needed to mount the file system without the "Read only" flag. The syntax above was correct.

However, I was disappointed to notice that this app (apparently) makes its own sub folder (named "NeGO3") and only indexes files in this sub folder. Which means that the app (apparently) cannot index and display already existing files in this volume.

Any way to fix this, or is this app unusable as a web frontend for the files in my backend?

Thanks again.