Add customized help on CLI

It is possible to specify customizable key/value pairs at the end of the command line to an installer.

e.g. 

installer.exe [options] command <args> <key=value>

However, as far as I can see there is no way to supplement the help that is output when you run: 

installer.exe --help

It just displays the "out-the-box" vanilla help provided to all QtIFW based installers.

Suggestion: 

Make it possible for customised help text to created by installer creators and output in response to --help.

Minimum requirement: probably add custom help in addition to the "default" help, but perhaps make it possible to replace the original as well?