Nickle my dd could vomit on command, she was lactose intolerant but it took us a while to work it out so she threw up a lot and in the end could do it if she was upset or wanted to avoid something.

Marushke it's a tricky thing to work through, consistency and sticking to the routine is the key but it's difficult when she is rebelling so hard. You need to find something that will make bed time a positive time for her, maybe a special blanket, a book she can read or a toy?