RadTreeView for Winforms does not support this functionality. You can define some graph of objects and use Tag property of the tree nodes to keep the reference to your business logic.
I hope this information is useful. Let me know if you need further assistance.
Q2’11 SP1 of RadControls for WinForms is available for download (see what's new); also available is the Q3'11 Roadmap for Telerik Windows Forms controls.