Yeap, it is a pain when the macro recorder doesn't give us anything.
This is working for me
Code:
Sub Macro1()
Dim aCC As ContentControl, xPart As CustomXMLPart
Set aCC = ActiveDocument.ContentControls.Add(wdContentControlText)
aCC.Title = "Title"
Set xPart = ActiveDocument.CustomXMLParts.SelectByNamespace("http://schemas.openxmlformats.org/package/2006/metadata/core-properties")(1)
aCC.XMLMapping.SetMapping XPath:="/ns1:coreProperties[1]/ns0:title[1]", Source:=xPart
End Sub