Ok, I finally understood why it didn't work for me. I am too much accustomed to Windows' standard volume shares (HOSTNAME/x$ where 'x' is the letter of a volume) and I assumed filesysbox would have supported them, as like as it does for explicit user-made shares. So the current experience I have is
MYHOSTNAME/D$, C$ or N$ are NOT working
while
MYHOSTNAME/SHARE is working
althoug SHARE must be something that I explicitly decided to share with Windows' own commands. So, if I create a MYHOSTNAME/DISK_C share for drive C, it will work with filesysbox.
Any hope to see Windows's standard default shares supported as well?
Moreover:
Also if you didn't add Activate=1 as explained in the readme you have to manually activate the file system by doing something like "dir SMB0:" after it's been mounted.
I have added the line Activate = 1 to the Dosdriver file, but I still need to access the directory some way (either with CLI or placing the volume name in Magellan's apposite field) to have the device actually mounted. Maybe I should try with the icon tooltype?