[kobes mama]

We've had Kobe for about three weeks now and I was so surprised at how fast he got used to peeing on the wee wee pads. But for some reason he wont go poopy on the pad. I've tried laying out another one because I've heard yorkies can be quite particular about peeing and pooping in the same place. That didn't work he just ended up peeing on the other on too.
He's picked this one spot that's behind my desk. I guess he likes it because no one can see him. So I started off small just putting down one pad along one side of the desk where he usually went. That turned him off and he found another spot behind the desk. This went on until I finally gave in and covered the whole are with pads.
I'm not sure this is going to teach him that he can't go behind the desk. I even tried blocking access but some how some way he finds a way to get back there.
Please help me! Any adivce it good advice at this point!