RadTreeView does not support command binding since it is not a command source. I've added an item in our public issue tracking system
called "TreeView: CommandBindings support"
which will be available for tracking and voting tomorrow the latest. If this item gathers enough popularity we will definitely implement it.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items