I had the same problem with my new Legend Cx a few days ago. I found that the points show up on the map at the 300 ft resolution. I am suspecting, though, that my real problem is that I have not yet installed the City Navigator software (waiting for version 8). Since I see the "Custom POIs" icon in my Find menu, but no "All POIs", I'm thinking that perhaps custom POIs rely on having the detailed maps loaded. I'll know for sure when v8 arrives. Could this be your problem as well?
Justin