Hey WoodWorks (David) Thanks!
...so that's +2 on the Motoriley's bmhfepr idea.
I'm lookin' at your setup there and I see a strut just in front of the turn signal. That looks like it is right in the way...I think. It's the Quick-Lock rack you have right? Did you relocate the turn signal like the pic on Twisted Throttle? Either way using the turn signal as a reference it looks like it won't fit.
In any case I think you may be better off making the Rotopax bracket fit to the inside of your rack...or even as I have seen some pics show mounting the bracket right to the inside of your Caribou case...
I do like Oregon though...and I'm always up for a ride.