在EF4.1中正确地从上下文中附加和分离实体

I am trying to implement caching mechanism for entities. And to use the entities correctly and seamlessly with the caching i need to detach the entity from the current context before i put it in a cache and attach it back the the new context when i get it from the cache. (My context lifetime is per http request)I am trying to implement caching mechanism for