1) Replace the L bracket with a stronger one
2) Use 2 fender U braces - one in front and one in the rear of the forks
3) Remove the front fender altogether
Front fenders can be quite dangerous if they come off at high speed and wrap around the front rim. I hope that Juiced covered your new front fender under warranty? If not please let them know about this problem as it seems like a serious design flaw which they need to fix.