I finally figured out the mitered binding tool and don't use it. i do 2 1/2 inch binding strips. then when coming to the ends, i over lap them, take a small ruler and lay it on the left end which i fold back over the ruler until the fold meets the cut end of the right binding strip. then i measure 2 1/2 inches of the fold and trim the rest off.
then take the left binding end, open it up flat, then take the right binding strip turned over so the right sides will touch , then pin on the diagonal. open out and make sure it will lay flat, then take to machine and stitch. then trim off excess and flatten out and finish stitching down on front.
same thing the directions say to do.