Get html tag in IInternetProtocolRoot::Start

Question

Is it possible to get html tag which initiated the call IInternetProtocolRoot::Start?

STDMETHODIMP MyProtocol::Start( LPCWSTR szUrl, 
    IInternetProtocolSink* pOIProtSink,
    IInternetBindInfo* pOIBindInfo, 
    DWORD grfPI, HANDLE_PTR dwReserved )
{
    LPCWSTR tag = ???

    ...
}