With the drain all installed, I layed down a piece of 3/4″ plywood for the new shower floor.  I also added some 2×10 blocking to attach the new shower pan to.  This was the point were I discovered a significant problem.  The copper vent pipe (on the right hand side of the picture) stuck out about 1/4″ beyond the studs.  Since I couldn’t move the vent pipe, this meant that I would have to add some sort of wood strips to the walls to allow the Durorock to lay flat.  This was also the point that I realized I needed a framing hammer, as the little hammer I generally use was not up to the task of nailing in the 2×10’s.  However since I was feeling rather broke at this point, I decided instead to use some galvanized screws instead.