Assignment Operator Problem on Based and Derived Class

Hello all, I am confused on the correct assignment operator that
should be implemented on the derived class. I refer to the document
found at :-

http://www.icu-project.org/docs/papers/cpp_report/the_anatomy_of_the_assignment_operator.html

which the author recommence not using "virtual" for assignment
operator. Hence, I provide the following implementation.

#include <iostream>

using namespace std;

class B {
public:
    B(int i) : b(i) {}

    B& operator=(const B& me) {
        if(&me == this) return *this;

        b = me.b;

        cout<< "b assignment"<< endl; return *this;
    }

    virtual void fun() { cout<< "b: " << b << endl; }

private:
    int b;

};

class D: public B {
public:
    D(int i) : B(i), d(i) {}

    D& operator=(const D& me) {
        if(&me == this) return *this;

        d = me.d;

        B::operator =(me); cout<< "d assignment"<< endl; return *this;
    }

    virtual void fun() { B::fun(); cout<< "d: " << d << endl; }

private:
    int d;
};

int main()
{
    cout<< "main"<< endl;

    B* b0 = new D(100);
    B* b1 = new D(200);

    (*b0).fun(); // "b: 100"
                    // "d: 100"
                    // printed. Correct behavior.

    *b0 = *b1; // "b assignment" printed. is this the correct
expectation?
                    // shall we expected "b assignment", followed by "d assignment"
                    // to be printed? If yes, what shall be the correct
implementation?

    (*b0).fun(); // "b: 200"
                    // "d: 100"
                    // printed. Now the result is "half-baked". The based class are
                    // being assigned properly. However, the child class is not

    delete b0;
    delete b1;
}

It seems that for me, the assignment operator implementation for
derived class is not correct (At least it shall not produce "half-
baked result) May I know what shall the correct implementation for
that? Any suggestion are welcomed.

Thanks!

cheok