Swap the fork, while you might be able to rig up something that works for a short while if it slips at all ever and falls into/onto the wheel you are going over the bars.
I have one of these myself and a blackburn mtf style one that mounts the same way, mounting onto mudguard mounts or whatever they are at the lower end of the fork is lots better than that one you linked too(I had one before and all that happened was the bolts on the right angle bits by the brake bosses undo from vibrations/use and it falls all over the place).
Swap the fork, while you might be able to rig up something that works for a short while if it slips at all ever and falls into/onto the wheel you are going over the bars.
I have one of these myself and a blackburn mtf style one that mounts the same way, mounting onto mudguard mounts or whatever they are at the lower end of the fork is lots better than that one you linked too(I had one before and all that happened was the bolts on the right angle bits by the brake bosses undo from vibrations/use and it falls all over the place).
http://www.planetx.co.uk/i/q/BRADFR/vavert-advancer-front-rack