I'm no expert, but just set this router up myself and agree you should see them all. However, are you sure the devices you are trying to connect to the router wireless are 5ghz capable? I assume you know that unless they are, they will only be able to "see" the 2.4ghz band.
Incidentally, for the price - this is a great deal. Unless you need more options for tweaking and can live without gigabit - hard to beat this on performance and price.