property Item.UserData as Variant
Associates an extra data to the object.

TypeDescription
Variant A Variant that specifies the item's user data. 
The UserData property associates an extra data to the item. The UserData property is not used by the control. The UserData are of Variant type, so you will be able to save here what ever you want: numbers, objects, strings, and so on. Use the RemoveItem event to release any extra data associated to an item, if case.