Documentation
Configuration / SessionAuthenticator.config_prefix
This option enables override any config option from a session, the value of this option will be used as a prefix when it looks though the sessions for config options.
Please note that the prefix is REQUIRED and set to moxiemanager by default in the config file.
$moxieManagerConfig['SessionAuthenticator.config_prefix'] = "
moxiemanager";
<add key="SessionAuthenticator.config_prefix" value="moxiemanager" />
So if you wish to overwrite the rootpath using sessions.
$_SESSION["moxiemanager.filesystem.rootpath"] = "/some/root";
Session["moxiemanager.filesystem.rootpath"] = "c:\some\site";