As I said very early on here, I don't care if the girls watching this watch it for the same reason as other people watch porn, just be honest about it. Be honest about the fact that the men in Twilight are about as realistic as the women in porn. For starters, at some point in a romantic relationship, the guy's going to want to have some sex - the opposite of what Twilight will tell you. We're not all only after one thing, but that doesn't mean that one thing isn't one of the things we're after.
I quite happy for teenage girls to fantasise about some pathetic girly vampire if they want to but only if we're willing to accept that they have the ability to distinguish fantasy from reality. I'm only willing to give them that much credit if we're also willing to give the same amount of credit to teenage boys and stop telling them that video games are turning them in to mindless killers and that it's not okay to read comic books where the women aren't drawn realistically. If it's okay for girls to like the guys in Twilight, it's okay for boys to like Power Girl, okay ?
Unlike most others here, I'm not going to say it's bad for a woman to enjoy being sexually submissive, either, as long as it's not presented as being the default. I've encountered plenty of women in my time who enjoy being submissive and none of them would particularly appreciate being told that what they enjoy is wrong. Telling a woman how she should enjoy her sex life isn't exactly the feminist ideal.