One more thing:
Is it possible that I mount different shares from the SSD with different login details?
It seems that all shares use the same login.
Once I have entered the login details in Windows to access one share, all other shares are accessible as well. I would like to avoid that.
(e.g. when a crypto-trojan hits me, it shouldn’t be able to access all shares)
Unfortunately this is not possible from the web interface. However, you can access the samba service via SSH and try setting up different logins for different shares manually.