My management server, print server and networked printer do not belong to the same network segment. How can this be installed?

PrintUsage does not require any specific networking configurations to function, if the ports used by the database, printer and print server can be access between networks, theoretically the system can be installed over a Wide-Area-Network.
However if installing the system between different networks or subnets, you should add the print server via PrintUsage management console.