I'd like to see you resolve this rather than bypass it. I was looking at changing to one of these to solve my blue tint problems and an FF filter is definately the way to go.
I found this tip on the Hutech site :-
Front-mounted filters do not affect the camera's autofocus operation but, when installed, preclude the use of Canon EF-S lenses or
some lenses designed for APS-C sized sensors. These filters also affect the closest focusing distance for each lens.
And
this review does not describe any of the problems you have.