This might help
I believe the article that addresses this is located Here -> modifying_custom_form.pdf
It would definately be nice if WA would incorporate the form designer with DA. I messed around with this over the weekend and I've come to the conclusion that it is almost easier to use DA for creating only the results page and then creating the input and update forms with FB. Your mileage may vary :) I will be happy when WA comes out with some more tutorials/videos on using the FB. It is a great tool but IMHO has a very steep learning curve.