Someone referenced this in another thread and so I thought I'd answer, even though it has been a very long time.
My suspicion is that you're not seeing or the devices aren't sending the IAmRouterToNetwork messages. Most likely this has to do with them going to broadcast addresses and your having bound a specific address. So, the operating system may not be delivering those broadcasts to your LocalDevice. You could try binding the address 0.0.0.0 or just zeros in the subnet bits, like 192.168.0.0