Toast通知在windows 8应用程序中不工作

我有一些带有警报场景的吐司通知。我使用了下面的toast模式，但是当发出通知时，没有按钮(贪睡或解散)。这是我的xml内容。那么为什么我不能使用这个toast命令呢?

    var contentString = "<toast duration='"long'">'n" +
                               "<visual>'n" +
                               "<binding template='"ToastText02'">'n" +
                               "<text id='"1'">" + alarmTitle + "</text>'n" +
                               "<text id='"2'">" + alarmNote + "</text>'n" +
                               "</binding>'n" +
                               "</visual>'n" +
                               "<commands scenario='"alarm'">'n" +
                               "<command id='"snooze'"/>'n" +
                               "<command id='"dismiss'"/>'n" +
                               "</commands>'n" +
                               "<audio src='"ms-winsoundevent:Notification.Looping.Alarm2'"'n" +
                               "loop='"true'"/>'n" +
                               "</toast>'n";