cat urine odor in carpet

Question
What product will really work on old cat urine odor in carpet? We did not know about it until it was several days old. We have used Natures Miracle which actually made it smell worse, Stink Free enzymatic cleaner, we have steam cleaned all to no avail. We left the product on the proper time and followed directions. We soaked all the way to the pad and concrete below. The urine smell remains. Please tell me if there is a product that will actually get rid of this horrible smell! Thanks!

Answer
Here is a previous answer I gave to someone:
I have used a product in the past called Feline Elimin-odor but it only comes in small bottles from the vets. There is a vet online that sells a product called Zero Odor I think and it is reportedly pretty good.

Here are some more:
What Odor? by
www.what-products.com

Anti Icky Poo!
http://www.catfaeries.com/cleanup.html

http://www.petproductadvisor.com/store/mc/zero-odor-dog.aspx?utm_source=petplace...

be careful with that one, not sure it's for cats but if you put it on the carpet it should be safe.