hello kim,
something you might consider is to get an expen or a gate that chewie cannot climb out of. (someone suggested play yard for children, you can check that out) and since you said that you are not having any luck with the pee-pad, one thing you can try is making a little potty box for him.
I made this for milu when I first started potty training her. Basically you buy a plastic container, soil, and sod. drill holes at the bottom of the plastic container and place the top at the bottom of the container so water doesn't get through. put soil in the container, then put sod on top of it. Milu knew what the little box of grass was for right away, and would go potty there whenever she needed to.
You might want to have a few different boxes so you can switch them and rotate using them so it doesn't get too gross. But i would definitely make just one first and see if it works out for chewie.
Hopefully i am explaining this ok and not making it too confusing? let me know if you would like to give it a try or if you have any questions.
(i stopped using these grass boxes because pee pads are a lot easier to deal with)
GOOD LUCK!
