Sync Project with SharePoint Task List

Project Server 2013 comes with 4 new methods, as documented in the SDK: CreateWssListSyncedProject, SyncProjectWithWss,ReadProjectSyncSettings andUpdateProjectSyncSettings.

But I can't get these methods to work for an existing project. So here are some questions:

• Can I use these methods to sync additional fields in the Task list with Project Server for a SharePoint Task List project?
• If yes, do I have to create this project by code or does it also work with SharePoint Task List projects created in PWA?

What I tried already:

I created a SharePoint Task List project in PWA. I want to use the UpdateProjectSyncSettings method to add additional fields to the sync. But the methodReadProjectSyncSettings always returns an empty dataset (count for all datatables = 0 in the result dataset). As documented in the SDK I usedSyncProjectWithWss before usingReadProjectSyncSettings, but that makes no difference.

Anyone can help me with this?

Or did I misread the SDK and are these methods for a different scenario? If so, which scenario?

Thank you!