How to work with COM classes and std::map

Hi,

I've this situation:

---------------------------------------------------------------------------

/*
 * CH 1 -> [KEY1][KEY2]...[KEYn]
 * CH 2 -> [KEY1][KEY2]...[KEYn]
 * / \
 * CComPtr<IWaveStream>
 */
typedef std::map < std::string, CComPtr<IWaveStream> > t_streams_map;
typedef std::map < short, t_streams_map >
t_ch_streams_map;

STDMETHODIMP CAudioPlayer::CreateStream(BSTR key,
                                        short channel,
                                        IWaveStream** ret_stream)
{

  std::string sKey((char*)_bstr_t(key));

  CComPtr<IWaveStream> iStream;

  HRESULT hr = CComCoClass<CWaveStream>::CreateInstance(&iStream);
  if (SUCCEEDED(hr))
  {
    //Store the object into the map
    streams_map_[channel][sKey] = iStream;

    if (ret_stream)
      iStream->QueryInterface(IID_IWaveStream, reinterpret_cast<void**>
(ret_stream));
  }
  return rv;
};

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

STDMETHODIMP CAudioPlayer::GetWaveStreamObj(BSTR key, short channel,
IWaveStream** pVal)
{
  if (pVal)
  {
    //Find the object in the map
    t_streams_map::iterator it = streams_map_[channel].find
( std::string((char*)_bstr_t(key)) );
    //If I found it, I return it.
    if ( it != streams_map_[channel].end() )
      return it->second->QueryInterface(IID_IWaveStream,
reinterpret_cast<void**>(pVal));
    return S_OK;
  }
  else
    return E_POINTER;
};

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

void CAudioPlayer::FinalRelease()
{
  for (t_ch_streams_map::iterator map_it = streams_map_.begin();
       map_it != streams_map_.end();
       map_it++)
  {
    for (t_streams_map::iterator item = (*map_it).second.begin();
         item != (*map_it).second.end();
         item++)
      (*item).second.Release();
  }
};
---------------------------------------------------------------------------

In the CWaveStream class I have a member *m_stream (that is a _simple_
pointer to another class). This member is correctly initialized in the
constructor.
When I call CAudioPlayer::GetWaveStreamObj from the client, I get the
object but its *m_stream member is became 0!
Also, when I terminate the application the CAudioPlayer::FinalRelease
() is called but CWaveStream::FinalRelease() is not!

Someone see errors in my code?

Thanks!
Daniele.