One of my adult cats cant get the hang of the kitty litter box, either. Never had a cat in my life that didnt naturally take to it but one we have now just cant get the concept. He will, however, get into a particular cabinet and go . We had to put child proof things on the cabinet doors to keep him out. He has finally decided to go outside- thank goodness! But he is precious. He is laying on the foot of my bed right now.
Congrats to you and Tommy, Hamster! ME-WOW...