Com Server: .tlbimp.exe does not recognize methods with pointer parameters

Question

I am writing a comserver that have a pointer as parameter:

STDMETHODIMP TServerDidleComTestImpl::GetMyObject(IDummyComObj** outObj)
{
  //Do stuff
}

When I am writing a client in c++ I have no problem with this method, but when trying to write a .Net client the tlbimp.exe says:

Type library importer has encountered a method with an unexpected [out, retval] parameter

What should methods that are returning interfacepointers look like? If anyone know of a tutorial/example on this subject I would bee grateful.

OleView declaration as requested:

HRESULT _stdcall GetMyObject([out, retval] IDummyComObj** outObj);