Now this is good news! ABA followed by an Aerial Wall Attack, ABA and an Aerial Attack will fill 99% of her Slam Meter. Even if she interrupts just one move, it will always be filled full. It does work on every character, though the hard part is the transition to the Aerial Wall Attack in addition to being near a wall. I did all of this on Romeo Drive, for stage legality purposes though it could work on the other legal ones. With practice, it could become easy to do.
A soup grab anti-air replacing the first ABA will still fill it to 95%, in addition of being a little easier to do.