You're overthinking this.
The fence is just square steel tubing with plywood or plastic faces screwed onto it, so just cut a bit off the end! You can rent a metal-cutting chop saw (or buy one cheap at Harbor Freight like I did) or use a hack saw. Just remove the faces first and cut those down to size with a regular wood-cutting miter saw. You might have to do a bit of cleanup with a file or sandpaper after you've made your cuts.