I guess the very first round needs to be detected quite rare, but if someone will still need this, one could solve it this way:
Code:
#include <amxmodx>
public plugin_init() {
register_event("HLTV", "event_new_round", "a", "1=0", "2=0")
event_new_round()
}
public event_new_round() {
server_print("NEW ROUND")
}
Like i said it's not fired on map startup because the game know that it will not have an effect on the client side because no one is connected yet.