After that I tried to
mount the folder via its full name (/var/...), but the console is saying:
mount: can't find /var/xxxxxxxxx/xxxxx/xxx/ in /etc/fstab or /etc/mtab
Thanks for your help,
EDIT: to complete my issue, I can actually see the unmounted folder, but I can't upload via FTP anyfile in it, although creating files via the console (touch test) does work.