Pregnancy on non vanilla follower

[Arcturus7777]

I have a non vanilla follower with a Way different body type than my un7b. I think she is unp skinny.

So I want to add pregnancy weights. I copied, using bodyslide outfit studio, the belly weights from my un7b body to female body-0 and 1, but pregnancy is not showing. She has her own female-skeleton.nif.

Can I copy weights to female-skeleton.nif?

I can not use the skeleton I am using with my main, as it has a vagina, and will really mess up how she looks.

Any suggestion?