Is it possible to reload radio selection elements in monotouch.dialog reflection api at runtime?

dialog reflection api to populate my radio group in my taskDialogController class:

[RadioSelection ("Oggetto")]
public int CurrentSbjct { get; set; }
[Caption("Oggetto")]
public List<string> CntctSbjct { get; set; }

in the class constructor I initialize the radio selection: CntctSbjct = OCLS_Utility.getNames ();

Now at runtime I want change the radiogroup values: CntctSbjct = ...;

I call the method taskDialogController.ReloadData();

But the radio selection elements doesn't update! Isn't possible to modify radio selection elements with reflection api? Thanks.