The search with square brackets does not work, why? See Pictures...

Sub Test()
Dim oSelection As ObjectItem
Dim oObjects As ObjectItems

Set oSelection = Application.Selection.Item(1)

Set oObjects = oSelection.FindObjects(aucObjUnspecified, aucSearchHierarchical, aucTypeUnspecified, aucAttrComment, aucCondEqual, "Test [Z]")

MsgBox oObjects.Count

End Sub