If the problem is just the way the seams lock do just what Judy363905 does. Just snip the seam allowance on one of the seams you want to lock together and press the end of it in the opposite direction. It should not interfere at all with the seam staying together. I do this all the time. I snip the seam almost to the sewn line on an angle about 2" away from where I want to sew the locking seam. Press it over and you are good to go.
peace