Hi mcknight. You're right, you'll need to configure one of the cameras to use a different IP address than the other. To do this, edit the /etc/network/interfaces and /etc/udhcp.conf files on one of your cameras, changing 192.168.12.1 to 192.168.13.1. This should put the camera on a different subnet, which will keep them from fighting each other.
Hope that helps!