Why isn't I get the browser context in refresh case?   

I have multiple web browser control instances...

1. Default
2. Hosted in custom explorer bar

Now following code always gets me the browser making the request,
however, it doesn't in Refresh (using F5 or Refresh button) case. Can
anyone provide an alternative or better way to figure out the browser
in context while processing the request in OnStart()

/////////////////////////////////
// Code
/////////////////////////////////
HRESULT CInternetProtocolWrapper::OnStart(LPCWSTR szUrl,
IInternetProtocolSink *pOIProtSink,IInternetBindInfo *pOIBindInfo,
DWORD grfPI, HANDLE_PTR dwReserved,IInternetProtocol* pTargetProtocol)
{
        HRESULT hr = E_FAIL;

        // Get the service provider interface to get to the webbrowser
that made the request
        IServiceProviderPtr pServiceProvider;
        hr =
pOIProtSink->QueryInterface(IID_IServiceProvider,(void**)&pServiceProvider);

        // Get the webbrowser that made this request
        IWebBrowser2Ptr pWebBrowser2;
        hr = pServiceProvider->QueryService(SID_SWebBrowserApp,
IID_IWebBrowser2, (void**)&pWebBrowser2);

}

date: 22 Mar 2006 02:39:29 -0800   author:   Vijay B