We started to put translations in each related application so I think it would be better to put these in a new (if there is not already one) translation page in help application itself. See http://extensions.xwiki.org/xwiki/bin/view/Extension/Localization+Module#HRegisterawikitranslation.

Also don't look too much at old translation keys (first because you would be lost ;)). All your keys should start with "help.", "platform" grouping of modules and we don't repeat it in packages, configuration and localization keys names.