I was strolling by the Realms of Power: Magic page, and noticed that it contains a link to the Book of Mundane Beasts. I also noticed the cat famulus prominenetly turning its back to us on Erik's shoulder in the book's picture. Coincidence? I think not! I smell a rat! Or a cat! Or something!
Art & Academe says, on page 119 that "rules for training magical animals can be found in Realms of Power: Magic".