I have an Eagle FishElite 480 and recently got the add-on hot chips card for out west. In my area in particular, it's supposed to provide a high-def map of Flathead Lake where I do most of my fishing and playing as it is. The 480 sees the card - but I can't get the card info to display, so basically I still just have a gnereic gps screen. Unless I've missed it, the manual tells me nothing. Any ideas?