Hello SkyeFire,
Broadcast and Multicast are different.
If you need to do broadcast, you can only use UDP. From what I have seen in the EKI manual, it does not seem to be possible to emit broadcast frames in UDP and also not documented to register as a server for broadcast messages. Broadcast sockets need special initialisation options.
For multicast, as Hermann says, you will also need to use UDP. Multicasts addresses are in the range of 224.0.0.0 to 239.255.255.255. Multicast is more complicated to use than UDP Broadcast and the mechanism is different.
Are you sure you need to is Multicast and not Broadcast to communicate with Kawazaki?