Speaking of pooping outside the litter box-any ideas for me?

[Tina B and crew]

Frodo is still doing it...I think I've tried everything and so far nothing as worked. She was just at the vet for a complete workup and everything came back fine..bloodwork was beautiful, fecal was negative..everything AOK except her ears (which were cleaned). We later did find tapes in Khanada's stool, then in Gizmo's stool so we treated the entire cat population here for tapes...and then applied Advantage. I wonder if that could have been it? But she's been treated and I've seen no more tapes in any of the stools.

So the vet thinks it has to be purely behavioral. We've tried homeopathics and Bach Flower essences and while they have helped with some of her past behavioral issues they haven't worked with this. At one point she was peeing AND pooping out of the box. I've solved the pee issue by putting down puppy training pads and newspaper. She uses that just fine for peeing, but still insists on using the floor for pooping. Fortunately she only does it in the garage and not in the house, but it still means going out there and picking up poo on a daily basis. I've tried:

New litter boxes
Different size litter boxes
Covered litter boxes
Every type of litter including the kind made from paper, Feline Pine, Worlds Best, Cat Attract, crystals, pearls, plain clay, clumping clay, scented, unscented, S'Wheat Scoop, alpine shavings, beet pulp, rabbit food, shredded newspaper (have I missed any?)
I've got litter boxes in different parts of the house as well as in the garage
Cleaning them meticulously
Covering the floor where she poops (she just finds an uncovered spot)
Moving putting litter boxes where she poops (she just goes beside them)
Putting aluminum foil on the floor (she scratches it away)

I'm banging my head against the wall to know what to do next. Actually we are thinking of moving everything out of the garage, cleaning the floor really good and possibly putting down cheap vinyl flooring in one solid piece since it would be easier to clean than the cement floor I would think. Of course vinyl is porous so it might not be any better. I'm just hoping maybe some of you can give me some ideas I haven't tried yet.

[Spez]

Just a thought (You probably have already thought of this one, but it worked in one situation I heard of)

When she poops, remove the poop immediately and put it into a close by litter box, preferrably one that only that cat uses. Sometimes, doing this repeatedly makes the cat realize that their scent is IN the box.

Remove any soiled paper as quickly as possible. I know moving poop around doesn't sound fun, but it sometimes works - getting them focused on where their "special" place is. Let us know what happens - OK?

[Tina B and crew]

Thanks spez...I have picked it up and put it in the box when I'm cleaning...but the problem there is she doesn't use a litterbox period. I've done everything to get her to use the boxes but to no avail. I'm not sure why she will pee on her paper but not poo on it. I've tried putting paper and puppy pads down where she poops, but she just finds another place most of the time.