Wii Fit Plus?

We just purchased the new Wii Fit Plus and so far love it. I have found a couple quirks that I am trying to work out. I was only able to register one dog on Wii+. Someone suggested that I delete a Mii (as I had 7 Mii’s, plus the dog). I deleted a Mii so that only 7 users were registered, and it still won’t let me register another dog. Instead it tells me that since I deleted one of my Mii’s they are going to substitute a guest. I don’t want a guest. I want another dog. There is nowhere in the Mii channel to add a dog. Anyone have any other ideas?