Well, there are a couple of things that can cause what you are seeing.
1: The knife was ground extremely thin behind the edge and almost no matter how steep you sharpen it (within reason) there just isn't enough steel to make a wide-looking bevel.
2: The edge is sharpened closer to 20 degrees.
It's not that the edge is convexed. You will still see a convex bevel the same as you will see a flat bevel, but if you aren't seeing very much edge then chances are the knife is already very thin or needs to be sharpened a little bit steeper. I hope this helps.