Family announcement

I need ideas on how to announce using the whole family. I have two kids and my husband has 1. I don't want to leave my step daughter out, but at the same time she's not mine so I feel weird about the whole situation and don't want to piss her mom off. Any ideas on how to announce?! Thanks!

Edit to add... I love my step daughter very much and would never deny her as my step daughter. I said she's not mine by birth and I don't want to make her mom feel like I'm calling her my daughter (so no baby #4 announcements, etc). It's a touchy situation between me and her mom so I would never want to cross any boundaries.