Here is a website of some real nice home spotters that I have been carrying. I know this doesn't help for your immediate problem, but might be something you want to look into. We have been very happy with them and do get a lot of calls for them. The pet spotter is a nice enzyme with an odorcide.
Fresh urine, blot with towell, amonia 1to4 to nutralize, then blot. You can finish with v&w if you want, I never did on my carpet, but I would tell a client that to be sure. When my dogs were pups, we used this process and we had no stains and no odor afterwards. When you catch as its happening, this works every time.