Skuda25

I apologize if this has been reviewed previously. I tried to find the answer via search. Can someone please give me a detailed description of how to mount a Salsa top mount brake level to a left mount rear brake set up. I have Avid Canti brakes with Shimano 105 brake levels mounted with the rear on the left side of the bars. I only want to mount 1 top mount level for the rear brake. Any help would be greatly appreciated. Do I need a special cable? Do you need a special kind of "stop" to attach to the cable going from the road brake lever to the canti brakes? Thanks.