I am glad to hear that you were able to resolve the problem on your side.
I just want to note that when you update any server control property on the server through an AJAX call, you should make sure you update the control itself as well. This is true for all controls and not only RadControls and this is how MS AJAX works. If you test the same scenario with a standard asp control, e.g a button, you will get the same result and the Text property will not change unless you have updated the button with AJAX.
In case you encounter any other problems or you have any questions, do not hesitate to contact us again, we will be glad to help.
the Telerik team