They sell kits to help you if you dont want to hunt for your own round pan.
http://www.amazon.com/CitiKitty-Cat-...8166362&sr=8-2
if your cat is above 10 pounds you may wish to invest in a large steel bowl for the toilet, as the plastic stuff may not hold their weight. As the cat trasitions you can switch over to a colander so the urine strains right thru, but the solid waste still needs to be managed during training. its a process, and patience is key.