If ya wanted to you could add a spacer say 3/8ths thick to the back of your hub.Youd drill 2 holes 180degrees apart equal distance away from center to hold it on.You could make it,or have somone with a lathe make it any size you want.Then you could use the 2 front bolts on the lower case to hold the bracket.If ya really wanted high tech,the 2 bolts that hold the spacer on you could mill a slight 1/4 moon,slot so even after the hub is tightened you could adjust the timing by losening up the 2 bolts and turning the spacer a little.The spacer would hold the magnet.