Unfortunetaly I've no experience with Realizzer, but I guess this software understands Art-Net or sACN!? So if you output Art-Net or sACN from your onPC you should be able to see this DMX data in Realizzer.
Please remember that you need MA hardware to output more then one universe DMX.
It works now. Did not remeber to set the Microsoft Loopback Adapter to IP- Adress 10.1.1.1 and subnet 250.0.0.0. Since I did this the (virtual) Art-Net connection between Dot2 on PC and Realizzer work.