Microsoft Project Plan 3 Custom Column Data in Power BI Desktop

Good Day

I would appreciate some help please to access Project Plan 3 custom fields in Power BI desktop.  Underneath some explanation & examples.

I have created various different custom fields, in different projects, using MS Project Plan 3.  Underneath is one such field named "Reason Task Was Late" with a test entry.

I also download the following templates from github

Using "Project for the Web" and "Project" templates I managed to setup/connect and refresh the reports, all importing the relevant project data.  

The only problem I have is the data from the custom fields.  These are not reflecting in the reports.

Could you please guide me where to look for the data (table and fields) and/or the steps I need to follow include the data in the reports.

Thank you

Kind regards

Stephan Willemse