Unfortunately, you need the ability to have a signature field sign a specific set of fields as opposed to signing the entire form and this is a feature which isn't available in Designer 7.x and Acrobat 7.x. I could suggest alternatives (see the
Single Field Password Protected thread) but these would
not guarantee the integrity of the data previously entered in the fields.
Fortunately, I can say that we've been working on a solution for this problem which may be available in the near future but I can't make promises.
Stefan
Adobe Systems