Any way to age down a pet?

I know it sounds strange, but I write Sim stories, and find myself in the need of some flashback footage of one of my leading cat character when he was a kitten... except, at the time when I first started the story, I was unaware of the "save to bin" option and therefore didn't do so for my kitty until after he'd already aged into an adult, and additionally, I use an auto-save mod that has already over-written all my early saves from when the cat was that age. All my saves are with the adult cat. Since I can't "make a kitten" in CAS, I can't simply load my Pet into CAS, select a different age, and then save him to the bin, like I do with human Sims quite frequently when I need flashbacks of them at an earlier stage of life. Anyone have any ideas of how I can get my kitty in a "kitten form" once again? Any help would be much appreciated!