Registering adopted child under the adoptive fathers name

May I ask if me and my husband can adopt and register under my husband's last name my sisters's (non-muslim sister) newborn child. Due to some circumstances the baby cant be registered because the father wont allow to put it under his name. (Unfortunately they are not married), so we are finding the way to help the baby to be registered and that is why we came up with the idea of adopting the child instead. Is it permissible? There is no possibility to put the baby's name under her own father.