rainman

I sent a few parcels through Thailand Post's 'Registered Mail' service. It's not EMS, which can be tracked online, but I assume since it is registered, it should be able to be tracked, too? I'm using http://track.thailandpost.co.th/trackinternet/Default.aspx but that doesn't seem to return anything. Does anyone know if registered mail is traceable online through Thailand Post? Or EMS only?