( type , oScope , silent , signature )
type <String>The type of event, which is passed to the callback when the event fires
oScope <Object>The context the event will fire from. "this" will refer to this object in the callback. Default value: the window object. The listener can override this.
silent <boolean>pass true to prevent the event from writing to the debugsystem
signature <int>the signature that the custom event subscriber will receive. YAHOO.util.CustomEvent.LIST or YAHOO.util.CustomEvent.FLAT. The default is YAHOO.util.CustomEvent.LIST.