well chip.. you are right.. that's also a way to do it.. if.. you have some skies to meter from.. depends.. the event i was at.. was so late.. so the skies were all dark.. and therefor i had to do it the way i described.. but yes.. meter from the skies.. set flash exposure compensation to -1 or -2 that will do alot..
but like everything with photography.. the way to do it.. depends on the current conditions