Maxxair Vent Covers

I did a search to see if this was covered in the past and couldn't find anything. My question. I have a 2000 3023 that I want to put Maxxair vent covers on. I bought a cover and had it in the garage for more than six months. Today, I got out the ladder and was going to install the cover when I noticed that the vents are not mounted directly to the roof but instead to a board which raises the vent up off the roof. With this type of installation I am 1) not able to get the Maxxair cover to go over the wood spacer and 2) the brackets would not mount as per the instructions. Rather than try to immediately jury rig something I thought I would ask how you all have done it on your rigs.

Larry P. Steinmetz
Battle Ground, WA