The OPC DA Address space hierarchy is discovered using the ChangeBrowsePosition from the Root and BrowseOPCItemIds to get the Branches, Items and Properties.
The name returned from the BrowseOPCItemIds enumString is used as the BrowseName and the DisplayName for each Branch. See also clause A.3.1.5.
The ItemId obtained using the GetItemID is used as a part of the NodeId for each Branch. See also clause A.3.1.5.
An OPC UA Folder representing a DA Branch uses the Organizes References to reference child DA Branches and uses HasComponent References for DA Leafs (Items). It is acceptable for customized wrappers to use a sub-type of these ReferenceTypes.