Tyler stays in his xpen in the kitchen ANY time we are not home, at night when we go to bed, and whenever I can't fully watch him (like being in the shower or giving my daughter a bath). He has a bed, toys, food and water dish and a pee pad in with him. He uses the pad MOST of the time but still has a few mishaps here and there. During the day (I'm a stay at home mom) he gets to stay with us the whole day so I take him outside and he goes
So during the day he's not using his pads unless like I said I have to shower or go somewhere and he has to stay in his xpen! It works well for us so yes, I think that they can be taught to do both.