How about just noncommittal responses such as "yeah", "nah", "I don't know", "maybe"... you also want to consider your eye contact pretty carefully. Try to deny it as much as possible, but if you're working with her rather than just alongside her, you'll have to give her attention on work related topics. If it goes off work related topics, then what you can do is cultivate a bored look and break eye contact for longer and longer periods of time. With girls talking on boring topics I have found this to be extremely effective. Unfortunately, when you've suffered from "nice guy" syndrome you've tended to believe you have to give a person your full attention just because they are speaking to you... girls latch onto this and put you in the therapist role. So if you break eye contact, fiddle with phone etc, they quickly lose interest. It's amazing how quickly they pick up on the difference in vibe and modify their behaviour accordingly. Women are actually quite intuitive.
Ray