<% var sm = Html.MvcSiteMap();
((MvcSiteMapProvider.DefaultSiteMapProvider)sm.Provider).Refresh(); %>
....
<%: sm.Menu(0, 1) %>

<siteMap defaultProvider="MvcSiteMapProvider" enabled="true">
  <providers>
    <clear />
    <add name="MvcSiteMapProvider"
         type="MvcSiteMapProvider.DefaultSiteMapProvider, MvcSiteMapProvider"
         cacheDuration="5" />
  </providers>
</siteMap>

foreach (var c in from object c in HttpContext.Cache where ((System.Collections.DictionaryEntry)c).Key.ToString().Contains("__MVCSITEMAP") select c)
        {
            HttpContext.Cache.Remove(((System.Collections.DictionaryEntry)c).Key.ToString());

            break;
        }