This is kind of off topic. I had a topo map on my 60csx, then just recently bought Navigator. I then downloaded the navigator to the unit, then the topo disapeared. so do I have to always load everything at once, ie- Eastern U.S. Topo , and a couple states of Nav. or can I load Navigator once, and then maybe put in Eastern topo, then maybe next month add Western Topo. seems like there should be an easier way.