Sorry, one more question about this. Is it the case that jailing the sftp user won't work with openSSH as in this example
due to not being able to "mount more than one folder/device/partition/netshare in a particular location" as explained at the end of this post
I'm learning little by little, but I can see the problem if ISPConfig creates a site with two system users, one for the website and a seperate one for the ftp account; i.e. "web1" who is the owner of all website files and the ftp user "[CLIENTNAME]Username" who is also chrooted into that same directory.
Is this what is going on, or am I missing something?