Logging solar panel production

I have this kWh meter that records my production:

http://www.schukat.com/schukat/pdf.nsf/index/31F9485510BF4EE5C125755F00450AAE/$file/S7EEN.pdf (page7)

Can I simply connect the SO+ to the 5V and the SO- to a resistor and a digital pin of the arduino and then simply read it with a digital read? As shown here: http://www.youtube.com/watch?v=f6fF84rtFTs

Is it that simple? What value does the resistor have to be?

no,

check - http://playground.arduino.cc/Main/EEM12L-32AKWhMonitoring - how I did it with a very similar KWH meter.