I have been struggling to get Griffin to pee in his litterbox. He is in a dog crate set up with an added shelf. Whether the bottom tray was bare or covered with newspaper- he would pee on the tray. I tried covering the part of the tray that did not have the litterbox on it with a fleece blanket- he dug the blanket out of the way and peed on the tray.
Yesterday I cleaned his cage and then wrapped the fleece blanket around the tray and slid it in the cage so the fleece blanket is held in place by the crate frame. He has not been able to dig up the blanket- so he has been peeing in his litterbox!!!! Yeah!!! 
And when he does not use the litterbox he ends up getting his cage and himself yucky with his long ears dragging thru everything and him walking thru it. So now his cage is clean and fleecelined!
And he is so good when out running around the house- he does not pee inappropriately then- so it was so confounding that he would pee inappropriately in his cage. It was the exact opposite when I had Cotton- her cage habits were good- her couch and free run litter habits left a lot to be desired.