RadialMenuButton LabelSize throws cast error

[jupagose]

If try to assign
RadialMenu rm = NotesRadialMenu; // Defined at my xaml
RadialMenuButton btn = new RadialMenuButton();
btn.Label = "♪";
btn.Icon = item.CurrentNotation;
btn.Name = "Note_" + item.NoteId.ToString().Trim();
btn.Type = RadialMenuButton.ButtonType.Simple;
btn.LabelSize = 10;
NotesButtons.Add(btn);

---

When run
rm.Buttons = NotesButtons;

Throws

Exception thrown: 'System.InvalidCastException' in RadialMenuControl.dll
Additional information: Unable to cast object of type 'System.Int32' to type 'System.String'.

Actually I'm using latest nueget versión.
Coding with VS2015 Update 3
Project type UWP app