I am trying to do the same thing. I am using PLCSIM for ET200SP, KepServerEx for OPC communication and NETtoPLCSIM. As recommended I have tried:
1. Turning off firewall
2. Permit access using Put/get with remote partner
3. disabled optimized block access
Still I have no luck. For checking my laptop network I tried same thing with PLCSIM S7300 and it worked but same settings are not working for ET200SP. Can anyone help me?