Dear cat,
I am a female cat who likes to pee on fabric. If mom had carpet, I might pee on that (but she's too smart for me, and has wood floors, which work much better for her, since cats inevitably throw up once in a while).
She tried different cat litters : I actually liked the "cat attract" stuff, and used it, but for some reason, she stopped using it (note from mom: "Cat Attract"--which you can buy as a litter, or as an additive to add to litter--worked well, but it is rather expensive, since there was no way to keep the other cats out of it, so I went through a lot of it. If Mandy were my only cat, or one of two, I'd probably still use it).
Even though mom is a bit slow at times, she finally figured out that I don't like to pee in litter (I do my other business there, and we both agree that's a good idea). She got me my own cat pan, and a bunch of cheap bath towels (from some place called "Walmart") and it's all mine! She folds two 'pee pee towels' in half and puts them in the box, which makes it really easy for me to go on them, and cover up what I did (the towels cover it really well, just as good as her t-shirts and stuff!).
(Note to Beavs from Kathryn: unless you can permanently get the odor out of the carpet---which may take some professional help--your cat is very likely to return to the area and keep soiling it. The big problem is that the urine soaks all the way down through the carpet and the padding, and sometimes, unless the carpet is actually pulled back and a bacteria-based odor neutralizer is used to 'eat up' the odor-causing molecules, the odor will never be gone enough so that your cat can't smell it.
You could try putting a cat pan (or pans, if there are multiple areas) with Cat Attract in it in the area where he urinates, so he would use that instead, then gradually move the box to a better--for you--location.
Also, this may be a way of him marking territory, so hormone treatment might help---even though he is neutered, he may still feel somewhat 'manly.' Check with your vet on that.
How long did you try Feliway? They pretty much guarantee that it will work after a certain amount of time (but you have to be consistent with it).