FCP center and anchor points

I'm using FCP 7.
We shot about 10 training videos for a convient store.

After editing and getting approval, they noticed the cashier didn't have a name tag on, Big No No.

So I was able to get their name tags and I'm trying to add the tags to the video, it has to follow the path of the cashier.

I've been trying key-framing and moving, but doesn't look natural.

How can I make the tag (stick) so to say to the cashiers shirt? Can I even do it?

Thanks