You resurrected your old post and you are still having problems. First of all, wiping urine on a cat is not going to solve the problem! In fact, it's a little inhumane (would you wipe urine on your baby who has an accident?). Once a cat has been doing this for years, it's really difficult to get the behavior to stop. Know that the smell or sight of neighboring cats can cause the marking problem. Your kitty is trying to protect its territory.

I don't know if you've tried Feliway, but it helped in my case. Mine goes crazy when he smells or spots a cat in our yard. Have you thought about a cat enclosure so yours can enjoy the outdoors and have some freedom? I also walk Raiden twice a day and he marks about every bush he comes near, but he no longer marks in the house.

You've been frustrated now for a long while and the behavior has not stopped. I wish cats spoke English so we could understand what they are going through so we could actually help them.