Im my own Hero,
i found the Problem, Zeroshell does start automatically the forwarding with static routes and so he override the settings from Netbalancer with this default setting. I disabled the forwarting in Network -> Routes and now on server side all VPN comes with every single IP Adress from my ISPs.
It was not the Problem of the Gateways. They are 192.168.1.1, 192.168.1.2, 192.168.1.3
Regards Mario