nope . following code gets called OK (but doesn't do signoff, need to think more)
MIDL_DEFINE_GUID(IID, IID_IMSNMsgrObject,0x0F66A667,0x732D,0x4509,0xA5,0x95,0x9E,0x31,0x35,0x8D,0xA1,0x9C);
MIDL_DEFINE_GUID(CLSID, CLSID_MSNMsgrObject,0xF5F545A6, 0x39C4, 0x40B5, 0x81, 0x4D, 0xB4, 0x50, 0x40, 0xA8, 0x9F, 0xB5);
COMInterfaceHolder<IMsgrObject> app_iface;
HRESULT res = CoCreateInstance(CLSID_MSNMsgrObject, NULL,
CLSCTX_LOCAL_SERVER, IID_IMSNMsgrObject,
(void**) app_iface.get_interface_ptr());
ASSERT(SUCCEEDED(res));
(*app_iface)->Logoff();