Client side events not working after creating a wrapper over Telerik.Web.UI.RadDatePicker

Question

I have a wrapper class over RadDatePicker.

public class DateTimePicker : Telerik.Web.UI.RadDatePicker
{
    public DateTimePicker ()
        : base()
    {
        //
        // Some code her
        //
    }
}

Now, I have my own implementation here. I want to use the event's like DateInput-ClientEvents-OnBlur :

<mydll:DateTimePicker id="date" runat="server" autopostback="true" 
       DateInput-ClientEvents-OnBlur="alert('Ding');"/>

But, I couldn't get the OnBlur working. Not getting what did I miss.

Thanks. IO