Why is Cascading RM32s so difficult?

We just purchased two RM32AI mixers and are trying to cascade them using Universal Control but it is not working. Both units are configured with static IP addresses and both units are coected to the MOTU AVB switch. I can select one of the mixers in UC but never find the second mixer, or at least the correct IP address. This is such a difficult process I'm just thinking about sending them back. Why can't this process be easier? Why can't they just be cascaded through firewire?