Steam the tempeh for 20 minutes. Let it cool until it can be easily handled. Grate the tempeh on the coarse side of a grater, and place it in a medium mixing bowl. Stir in the remaining ingredients except the buns, and mix well. 

Place the buns on a dry baking sheet, cut side up. Spread the tops evenly with the tempeh mixture, spreading it to the edge of each bun. (This will help to keep the edges of the bun from burning.) 

Place the sandwiches under the broiler for 4 to 5 minutes. Watch closely so the sandwiches do not burn. 

Serve the sandwiches hot. They may be eaten by picking them up with your hands, or you can use a knife and fork.