I have this same question about buning a CD ISO image. When I burn I can only choose the "DVD" profile. The CD finished just fine and worked, so this is just a question really. Incidentally the program then miscalculates the CD write speed in the writing window as if it were writing a DVD (ie it says 1.5x instead of 24x or so).
I have the newest version 22.214.171.124.