How do you customize this help in CRM 2013?

It shows the following for a customized entity

It appears that the configuration of help pages in Microsoft Dynamics CRM 2013, On-Premise is no longer supported. In CRM 4 it was supported (Reference image 1). In CRM 2011, support was dropped (Reference image 2) and the suggested alternative is the Getting Started pane. In CRM 2013, the Getting Started pane was dropped from the sitemap (Reference image 3).
Reference image 1

Reference image 2

Reference image 3
