Hmm.. looking at the pics of both brackets, it looks like the Alphacool bracket might work. I cannot guarantee 100% that it will tho. Can't you just drill the holes in the case? Use screws with nuts & washers to mount it. It would be cheaper cost wise and save alot of headaches with the guessing game.
Also if you purchase the Alphacool bracket and that doesn't fit/line up with the holes on the pump or the case, you're still stuck. Know what I mean?