Is there some guide to do the same in a private environment?
I is... using an HTTP/FTP/Git server as the monticello repo (SmalltalkHub seems overkill).
Kilon:
I guess the main prerequisite is to have all the Monticello packages of your classes properly configured, and also the Metacello stuff in line (ConfigurationOf...).
Then it is a matter of setting up a new image through command line loading the needed Metacello versions and then your own.
You can do this in the context of a CI server or with a fresh image + cmdline in your own computer.
Regards!