Template class with template method specialized for itself

Lets say I have template class with template function. Example:

template<typename T>
class example
{
    T some_member;

    template<typename X>
    example& foo(X& val)
    { /* general stuff */ }

    // rest of class
};

What I'm failing to achieve is to make specialization for this method which takes as argument object of type example < T > (same type as caller's).