So doesn't sound like to bad a history for it. Its fairly cheap to replace.(pvc one) I wonder if you could drill some holes and use some cords or bail wire to secure it upward to the plow.
I have used a grader blade backwards for years, and slow is what its about.It gets done and without breakage. Sometime if its deep ill run it a few inches off the ground, and
cut a first pass and then drop down and finish it up.Its not much slower all in all.
Al