Firewall, with 2 internal subnets and 1 valid external public address

I was using my SUSE 12sp5 as firewall that was using 1 nic for internal LAN e the other nic for external (wan) with a valid IP address, so conected directly to internet.
I want to add a new nic to serve a new internal subnet (for cameras surveilance) butI cannot put this setup to work. All devices on this new subnet can not find the others subnets. Is there anything to set to make it run?

I have already set those internal nics as internal network, routing is enabled on LAN routing TAB (Enable IPv4 Forwarding), but it is not routing