Hi guys..I've the following problem..

I have a file called A.h and a file B.h. each  contains some struct like this: (the structs inside the two classes are different)

    struct Base
    {
        friend class access;

        template <typename Archive>
        void serialize(Archive& ar,const unsigned int version)
        {
            ar & fieldLength;
            ar & fieldMD;
            ar & fieldTime_Stamp;
        }   
       public:
            unsigned int fieldLength;
            unsigned int fieldMD;
            unsigned int fieldTime_Stamp;
   
           virtual void f(){} //to be polymorphic the struct
    };

    struct Derived:public Base
    {
.        ...
    }

So i serialize the struct in the classic manner:

    ....
 
    std::ostringstream archive_stream;

    boost::archive::text_oarchive archive(archive_stream);

    archive.register_type(static_cast<Derived*>(NULL))

    archive <<p;   // where p is a pointer to Base

NOW THE PROBLEM...
on the deserialization side, I follow the same (inverse) procedure...if I deserialize singularly the structs in A.h (without include in the project B.h) and the structs in B.h (without include in the project A.h) all works....but If I include in the project both the classes, the deserialization  works for one class, but  throws the "Stream error exception" in the  instruction   " archive >> m;" for the other...it seems a conflict in the registration class or something like this...
Any ideas?thanks...