A Kaos will never knife edge, as you have discovered. It was never intended that it could or even should. It took a change in the pattern to drive the change in model design to allow that sort of flying. Having said that, some of the earliest demos of knife edge flight happened way back in the '60's with models like Bosch's `Delphin', one of the first `fishy' fuselaged models with enough side area to accomplish the task, and with reeds too.
Evan, WB #12.