Good luck, mine won't go in covered boxes!
We've got six cats--a couple of them are okay with covered boxes, but most of them prefer open ones.
Thank you. Yeah, I know. But thankfully, covered litter boxes all they've ever known, so they're okay with it. I keep imagining my own home one day with a room totally devoted to kitty toys, with a door to a safe (screened in but huge) outside play area and one or more separate areas for cat litter. I know. Dream on!
Well, after a few days, I can tell you that my little jury-rigged inner-step is working! The litter trays outside the box are dry! Yeah! It's certainly not a perfect solution, but it does seem to be working.