Unable to extract task GUID from tasks

I can’t extract the GUID from the task. Any idea how I can get it?

If I’m not mistaken tasks, resources and other standard structures don’t have Guid properties at all. By documentation and xml scheme it’s available for Outlines and Extended attributes only.

It was available when i used the MS Project 2007 COM files. However, I can use the UID i guess. that is supposed to be unique.