There is a tutorial in the Tutorial Forum on cutting them with a round chain saw file before filing/grinding in the main bevel. This is a good approach if you have a file guide to use to keep from cutting into that pretty plunge when you do the rest of the bevels. If you are freehanding it I think you might as well not bother.
I have a piece of granite with the edge rounded over, that I wrap sandpaper around, and use this to lap my plunges after grinding the bevels in. I have an improvised file guide that I use as a fence to guide the blade as I drag it across the sandpaper. It is mechanically the the same as doing it with a file and guide but I am moving the blade instead of the tool, and this also works effectively even after heat treat, which files usually can't do.