I am sorry, I forgot to update this discussion as I had a reply from the support: I just had to right-click the range button to increase the range. This is quite unusual when you have a button with 2 arrows, which is why I dodn't find the trick by myself, but it works. In addition, it is not consistent with the standard Garmin GPS 500 that is in the 2D popup window. Anyway, it works, I just regret I can't have the terrain display like on the standard GPS 500.
Regarding the HSI problem you are talking about, I don't have it. I often fly using GPS guidance and the HSI works well, showing deviation from the programmed route. You still have to manually turn the needle to adjust it to the next waypoint bearing, but this is not a bug, it is normal and realistic.