with so many people not willing to provide useful tips hopefully this will help. my wife and i are toilet training our cats. our 4 year old cat started peeing in the toilet but pooping on the floor. the way we fixed this was (with training tray still in toilet) we scooped the poop up and put it in the toilet tray and closed her up in the bathroom for a few minutes. she would smell the poop, climb into the tray and cover up the poop. we did this to show her where the poop should be. after she covered the poop with litter we then gave her a treat. this technique seemed to work for us. give it a try
and to other readers, don't bother replying to tell me how unnatural it is for a cat to use the toilet. i keep a small stool in front of my toilet to give them the stability they need. less money spent on litter that's tossed into land fills makes complete sense to me!