Wow I ran across your post by chance and this is EXACTLY what my little Bella is doing....and no matter if I have the pads with the adhesive tape or put something to hold them down ....she tears them to shreds!!!!
and poops next to them. Not all of the time mind you. Sometimes she is great and poops and pees on them. I praise her like crazy when she does too...and she gets soooo excited and jumps up and down and does this little flips and all is just so wonderful...and then the next time she goes, she goes on the floor! ahhhhhhh, I guess I just dont get it.