You can do as luap suggested and drill holes in the bars or run them externally...that's what I chose to do when I put on drag bars a couple years ago. Using a dremel or an angle grinder, you can cut a notch in the bottom half of the controls so that the wires will pass through without pinching. I recently switched the drag bars out for clubmans and kept the wires running externally....it doesn't bother me, but I know others like the clean look of internal wires. To clean it up a bit, I slipped some black plastic corrugated wire looming over the cables since the black insulation on the original wires was looking a bit shabby.
If you end up cutting notches, be aware that your cutting/grinding can put tiny metal shavings into your switches (not good), so take care to protect the "innards" of your controls when you are doing the job.
If you want pics of what mine looks like, I'd be happy to share.