I was able to down load 250 waypoints from my Garmin Venture (handheld) to my computer and homeport. I then copies to sd card and then put them on my 73DV and 840XS. I tried the same with the 50DV and it will not do, what am I doing wrong. I tried to see what I can change for it to accept the GPX. files. Appreciate any tips or suggestions to solve this issue. I want to keep this unit at the bow.