As you mention to run schedule manually. I think you need to change the run syntax <value>? ? ? ? ? ? ?</value>
If you use jsp you should be able to change this value on scheduled-action-services-context.xml According to me , there is no meaning to run manually as name suggested "SCHEDULED TASK" since it tells us auto task.
Anyway try to change value through JSP , I hv no more idea how.