Hey I got these classes 'BaseObject' 'TreeNode' and 'Entity' Entity is a child of TreeNode that again is a child of BaseObject. both are declared as

typedef boost::shared_ptr<BaseObject> BaseObjectPtr;
typedef boost::shared_ptr<TreeNode>   TreeNodePtr;
typedef boost::shared_ptr<Entity>     EntityPtr;

Now I got a BaseObjectPtr and want to upcast it into EntityPtr. like:

BaseObjectPtr pBase( new Entity );

// throws a compiler error, at least at my compiler..
EntityPtr pEntity = pBase;

A example how to achive this would be nice :D Thanks in advance...