Can't Add Filter to a FilterGraph running on another Process

Question

I am trying to connect to a filtergraph via the Running Object Table and add a Filter.

I can stop and start the graph, but that is about it. I get an error. I can do this with the original GraphEdit, but GraphEditPlus and GraphEditNext and GraphStudioNext cannot. Error is VFW_E_NOT_IN_GRAPH.

CLSCTX_INPROC_SERVER I feel is wrong, but CLSCTX_INPROC_HANDLER doesn't work. I did use IDA on GraphEdit.exe and noticed they use CoCreateInstance with integer 23 which, doesn't seem to exist. CLSCTX_INPROC_SERVER is integer 1.

Here is some sample code? I tried the same thing with DirectShowLib with C# and I get the same error with both.

CoInitializeEx(nullptr, COINIT_MULTITHREADED); //MTA
CComPtr<IRunningObjectTable> pROT;
if (FAILED(GetRunningObjectTable(0, & pROT)))
  return 1;

CComPtr<IEnumMoniker> pEM;
if (FAILED(pROT -> EnumRunning( & pEM)))
  return 1;

CComPtr<IBindCtx> pBindCtx;
CreateBindCtx(0, & pBindCtx);

for (CComPtr<IMoniker> pMoniker; S_OK == pEM->Next(1, & pMoniker, NULL); pMoniker = NULL) {
  LPOLESTR pDispName = NULL;
  if (FAILED(pMoniker->GetDisplayName(pBindCtx, NULL, & pDispName)))
    continue;

  CStringW strw(pDispName);

  CComPtr<IMalloc> pMalloc;
  if (FAILED(CoGetMalloc(1, & pMalloc)))
    continue;
  pMalloc->Free(pDispName);

  if (strw.Find(L"!FilterGraph") != -1) {
    CComPtr<IUnknown> pUnk;
    if (S_OK != pROT->GetObject(pMoniker, & pUnk))
      continue;

    CComQIPtr<IFilterGraph2> pFG = pUnk;
    if (!pFG)
      continue;

    CComQIPtr<IMediaControl> pMC;
    OAFilterState fs;
    pMC = pFG;
    pMC->Pause();
    CComQIPtr<IBaseFilter> pSmartTee;
    hr = CoCreateInstance(CLSID_SmartTee, NULL, CLSCTX_INPROC_SERVER, IID_IBaseFilter, reinterpret_cast<void **>(&pSmartTee));
    if (SUCCEEDED(hr)) {
      pFG->AddFilter(pSmartTee, L "Smart Tee");
    }
    
    pFG.Detach();
    pFG.Release();
    pROT.Detach();
    break;
  }
}