I am at the point where I will be installing the 912ULS radiator on my model IV. But, I have covered and painted the aircraft and it seems that the photos in my circa 1997 manual show the radiator being installed under the cabin floor with the fuselage NOT covered but the photos showing the fuselage being covered do not have the radiator installed and I can't find where I missed instructions saying to install it before covering.

What should I do to install, cut the fabric and patch?