i completely understand what you mean when you say you'll use the knowledge to improve, but you're not looking for direct advice, necessarily.
as i haven't been in this situation, i really don't have any examples or direct advice to give. i just wanted to drop in and voice my concerns because...and this is just -my- view of things, so don't take this too much to heart...but it seems to me as though this is just bratty behavior - as though she wants someone to "break" her of her stubbornness. it's possible to be fiesty and be a submissive, but this seems more like...pushing things too far to me. i just know that many dominants i've met would not accept this kind of behavior because they feel that if the submissive does not at least act as though they -want- to submit or are -trying- to submit, even if they may have problems in the process, their time is being wasted. then again, a lot of people find this kind of play fun, and see the fun in the "breaking" of stubbornness and will.
i guess i'm just trying to say that maybe it shouldn't -be- this hard. i think the biggest thing is to sit down and talk to her and ask -why- she's acting like this, and what she wants to get out of it. this is not all your responsibility - it goes both ways. she needs to communicate her feelings as well. i don't think your flaw is that you're not forceful - it seems like doing anything but ignoring her behavior would just be giving in to what is a very selfish cry for negative attention.
good luck!