There is an area in front of the Glove box where you can zip tie it in, that is the spot it mounts in the 08.5.
Also, as long as you don't have Navigation from Mazda in the car, the antennae can be mounted under the center part of the dash, remove 2 screws and it pull up gently, My stock antennae got the wire broken when a tree limb fell on the back of the car and I mounted the replacement in the front under the center part of the dash.