Multiple inheritance/interface delegate through template function not working

Any thoughts on why TPureVirtual:: VirtFun cannot call the second
method.
Two compilers choke on it. Actually one works, but only if not using
an 'ISO C++ Template Parser.'
Why would the language allow the first version, but not the second?

Thanks.

// -----------------------

#include <iostream>

class PureVirtual
{
public:

    virtual void VirtFun() = 0;
};

template <long I, class T>
class TPureVirtual : public PureVirtual
{
public:

    virtual void VirtFun()
    {
        // 1.
        static_cast<T&>(*this).Done(I);

        // 2.
        static_cast<T&>(*this).TDone<I>();
    }
};

class ImplVirtual : public TPureVirtual<1, ImplVirtual>,
                    public TPureVirtual<2, ImplVirtual>
{
public:

    void
    Done(long I)
    {
        std::cout << "ImplVirtual<" << I << ">::Done" << std::endl;
    }

    template <long I> void
    TDone()
    {
        std::cout << "ImplVirtual<" << I << ">::TDone" << std::endl;
    }
};

extern "C" int
main( int argc,
      const char **argv )
{
    ImplVirtual impl;

    TPureVirtual<1, ImplVirtual> *pv1 = static_cast< TPureVirtual<1,
ImplVirtual>* >(&impl);
    pv1->VirtFun();

    TPureVirtual<2, ImplVirtual> *pv2 = static_cast< TPureVirtual<2,
ImplVirtual>* >(&impl);
    pv2->VirtFun();

    return 0;
}