[NTG-context] Creating PDF files which are editable in Adobe Reader

Hi, does anyone know how to enable the editing functionality in PDFs files? Adobe Reader 8.x seems to be able to edit PDFs which have been marked as such. (Editting: Highlighting and adding comment boxes + saving the modified files. See: http://www.adobe.com/products/reader/ -> e.g. Feature tour) I actually failed to find a description for this in http://www.adobe.com/devnet/pdf/pdf_reference.html (It might be hidden in TABLE 3.20, p. 123. I'm not good at reading standards and I'm sure Adobe won't make this feature too obvious.) Tobias, who finds Adobe Reader 8 a slow resource hog