spring webflow的问题,有谁知道吗?

Question

我刚接触spring webflow,我写了个首页index.jsp,通过首页跳转到welcome.jsp页面,在welcome.jsp页面有个链接,点击可以到一个说明页面.问题是在welcome.jsp页面这个链接不知道怎么写?
代码如:
<div class="foot_backto_top"><a href="#"><img src="images/fnc_${pc}_icon_top.gif" alt="Back To Top" width="10" height="10" border="0" title="Back To Top" /></a></div>
<div id="foot_footer">
     <!-- footer links -->
         <div class="foot_footer_links1"><a href="carBuy.htm?_flowExecutionKey=${flowExecutionKey}&_eventId=end">Terms of Service</a></div>
            <div class="foot_footer_links2"></div>
       <div class="foot_copyright">Copyright &copy; 2008 Trilogy E-Business Software India Pvt Ltd. All rights reserved. </div>
        <!-- footer links ends -->
   </div> 
我是这样写的carBuy.htm?_flowExecutionKey=${flowExecutionKey}&_eventId=end  但报错.异常如下:
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.webflow.engine.NoMatchingTransitionException: No transition found on occurence of event 'end' in state 'aslayout' of flow 'as-layout-flow' -- valid transitional criteria are array<TransitionCriteria>[[eventId = 'asfindACar'], [eventId = 'asusedACar'], [eventId = 'getReviews']] -- likely programmer error, check the set of TransitionCriteria for this state
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:488)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:431)
javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.carbuy.core.ui.filter.CarBuyFilter.doFilter(CarBuyFilter.java:58)
org.springframework.webflow.engine.NoMatchingTransitionException: No transition found on occurence of event 'end' in state 'aslayout' of flow 'as-layout-flow' -- valid transitional criteria are array<TransitionCriteria>[[eventId = 'asfindACar'], [eventId = 'asusedACar'], [eventId = 'getReviews']] -- likely programmer error, check the set of TransitionCriteria for this state
org.springframework.webflow.engine.TransitionableState.getRequiredTransition(TransitionableState.java:80)
org.springframework.webflow.engine.TransitionableState.onEvent(TransitionableState.java:107)
org.springframework.webflow.engine.Flow.onEvent(Flow.java:534)
org.springframework.webflow.engine.impl.RequestControlContextImpl.signalEvent(RequestControlContextImpl.java:205)
org.springframework.webflow.engine.impl.FlowExecutionImpl.signalEvent(FlowExecutionImpl.java:202)
org.springframework.webflow.executor.FlowExecutorImpl.resume(FlowExecutorImpl.java:222)
org.springframework.webflow.executor.support.FlowRequestHandler.handleFlowRequest(FlowRequestHandler.java:111)
org.springframework.webflow.executor.mvc.FlowController.handleRequestInternal(FlowController.java:165)
org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:858)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:792)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:476)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:431)
javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.carbuy.core.ui.filter.CarBuyFilter.doFilter(CarBuyFilter.java:58)