9. The charging system of claim 7 wherein at least some of the charging topic characterizing data messages comprise data selected from the group consisting of: requirement data for publishing proxies for a charging topic, requirement data for subscribing proxies for a charging topic,and charging event reporting requirement data for a charging topic.
7. The charging system of claim 1 wherein the transmitter is arranged to broadcast charging topic characterizing data messages for the charging topics to the charging proxies.