Not sure about that, once you've started on that road it can make things difficult.... the people I know sorted it out quickly between themselves without any difficulties. Would you be able to get some free advice from a lawyer regarding your position ? I'm not sure where you live, but in the UK a lot of law firms will give an initial consultation free, which would maybe give you an idea of your legal position.
perhaps if you asked your daughter to write a letter to her father explaining why she would like to live with you better than him he would see that she is capable of making (or not making) this decision herself. It also takes some of the pressure off of you in that it won't seem like you're trying to bribe her.
The suggestion that the other person left may also be worth considering. Her father may be unwilling to be a "weekend father", but if it's made clear to him that he will still have regular weekday visitation as well, he may be less hostile.
