WhiteAngel

Hello, I'm trying to use dualbox on l2skirmish.com server. In the situation when you already got 1 char in game and you are trying to login another one, just before entering the world (after authentication -> EULA acceptance -> Server selection -> Char selection) 2nd client is being shut down and in the chat of 1st account you got message: "[NameOfThe2ndAccChar] kicked by dualbox protection". Using VMs and l2net didn't help, the same behavior. Could someone explain which mechanisms can be used to determine that this is really dualbox usage and how to overcome this protection?