A long time has passed since that initial post...and indeed I managed to finalize the reading of the utility meters with an arduino connect to the home server.
I now have a real time graphic of each watt hour and each hundredst of cubic meter of gas used in the house. I did switch it off during the holidays, but the system was then synchronous with the numbers on the real meters. Enclosed is an image of the graphic for the last 24 hours of electricity usage. When the winter comes and the gas starts burning, I hope that the gas graphic becomes more interesting. Now it only shows little bars when we take shower and cook. I'll add the schematics soon.
Next step is to connect the doorbell to the server and broadcast to the network whenever someone rings, as well as taking a snapshot of course.