We remotely program S7-400s over the ethernet. Works very well - also very quick. Setting up the PC adapter is usually very easy? We only use the PC adapter to setup Ethernet communication - after that all comm is over the net. Siemens has an excellent article in their knowledgebase about remote programming over the ethernet. I've included a link below. Besides the Step7 software, you will also need to purchase Siemens SoftNET IE software - about US $2k I think.