how do is store CMap of CMap data

hi,

i want to use the CMap of CMap for storing some data

e.g.

class A{
    CMap<CString, LPCSTR,B,B&> mapB;

    CString name;
};

class B{
    CString name;
};

and now i want use the
CMap<CString, LPCSTR,A,A&> mapA;
on compiling here it was giving the error like
"'operator =' function is unavailable"
so in class A i added operator
void operator=(const A& ao_obj){
//what should i write here
}

then it compiled with 0 errors
and then i added data in map A

CString key="1";
A aobj;
aobj.name="SomeName";
mapA[key] = aobj;

Now at the time of retrieving this A object
it is not storing the value in the object
means
CString k1="1";
A objA;
mapA.Lookup(k1,objA);

so here it should store the value in objA
but it is not doing this
it is happening because of operator=
what should i write in 'operator=' function?