Hi Cesar Guinovart,
As the obsolete message for both properties states, the setters will be removed from the public API of RadTreeNode. That is necessary because by using these setters one can damage the treeview structure. This is why we decided to handle setting these properties internally.
The getters will remain and are safe to be used. Unfortunately, the obsolete attribute cannot be applied to the setter only. That is, even if you only use the getter of these properties (and not the deprecated setters) you will still get warnings.
We will most probably wait another Q release and then remove all obsolete members.
I guess you will have to wait till then.
the Telerik team