C++ Template class Inheritance, how to member type specification?

template <typename _datTy>   
class ANode{
typedef ANode<_datTy> _nodeTy;
public:
    std::vector<_nodeTy> childVector;
};

template <typename _datTy, class _nodeTy = ANode>
 ATree
{
public :
    void doSomeThing()
    {
        auto iter = _root.childVector.begin();
    }
protected:
    _nodeTy _root;
};




template <typename _datTy>
class BNode :
    public ANode<_datTy>
{
typedef BNode<_datTy> _nodeTy;
public:
    bool somethingExtends;
};
template <typename _datTy>
 BTree :
    public ATree<_datTy, BNode<_datTy>>
{
 ...
};


BTree<char> test;
test.doSomeThing();

This code problem is std::vector<_nodeTy> childVector. It's translate to std::vector<Anode<_datTy>> on BTree compile time.

But I really want this, std::vector<Anode<_datTy>> on ATree compile time, and std::vector<Bnode<_datTy>> on BTree compile time.

I don't use base class pointer like this std::vector<_nodeTy *>, on current architecture point.

how to any idea this problem? Thanks for your read.