Steel Fan, for some reason the picture isn't showing up that good on my monitor so I can't see exactly what you are talking about. Are you wanting to put a sharpened swedge on a knife that does not have one at all? If so, yes, you can do it with your belt grinder. How easy it will be, and how long it will take will depend upon what grinder you have and how high the quality of belts you have available are.

Usually if I am putting a swedge on the spine of a knife that doesn't have one to begin with, I will use the platten on the grinder. Most all of us are using the slack belt method when we are convex sharpening the edges of our knives, but that is not usually what you are looking for when grinding a swedge. Although, there really isn't any reason why you couldn't do a convexed swedge.

When I grind in a swedge I take a scribe and make a mark down the middle of the spine as a referrence point or a "grind to" point, and I also make a mark accross the spine where I want the swedge to begin and end, as well as down on the blade however far down I want the swedge to go(draw a devided box if you will). Also, doing this modification using the "edge in" grinding method will give you a much better view of what you are doing if you are able to do it with your grinder. What I mean by that is to grind with the belt running into the spine of the knife or whatever area you are grinding on rather than the belt running away from it like you would normally do. I just switched over to this method not long ago and it works very well, especially for a mod like this.

You will diffinitely need to keep an eye on things and not let the steel get too hot. Just keep that bucket of water right there by the bench and dunk away. When you are using the coarse grit belts it isn't going to heat up near as fast as it will with the finer grit belts.

I don't know if any of that helped you or not, but if you have some specific questions I'll try to help if I can as I'm sure Vic, Knife Guy and maybe some others have some good ideas to offer as well.