[NTG-context] adding forms to an existing PDF document

Dear list, I have received a PDF document, in which I have to add fill-in fields. The wiki provides good information on how to do the widget part (of course, most comes from “Widgets uncovered” by Hans ;-)). After searching in the wiki, I realize that my question may be stupid. But I have to ask it: is there any other way to get absolute positions for those field avoiding layers? Many thanks for your help, Pablo -- http://www.ousia.tk