There's some code that always turns the password field off if membership review is turned on. You'll have to disable that.
It doesn't work with the membership review because my initial thoughts were that the password would have to be stored in the membership review list, which would be insecure. If you want to do this though, you'll have to add a new field to the membership review
list, and then store and retrieve the password from there.
Another way around it might be to simply store the password with the membership user that's created as a placeholder during the inital user registration. Right now when the member is approved, that user is deleted and recreated. Instead you could just use the
existing user, which should have the user's password. This is on my todo list for the FBA Pack, but I have not gotten to it.