When I import a pdf document to the designer to add text, the text which is already there goes up or down, above other text which is already there.
To replicate this, download: http://www.cra-arc.gc.ca/E/pbg/tf/5000-s11/5000-s11-06e.pdf and import it into designer. Then read the text after saving it.
Using Adobe Designer 7.0
Currently I am using "drawing markup tools - text" in the Acrobat 7.0 Pro to write text into the document. If there is any other way using Acrobat (not designer) to write text into documents please let me know.
Or you could just use Acrobat's "Form Tool" add your additional text as text fields or buttons and import the icons and set them as read only and then add any additional fields and the necessary calculations or interactivity as needed.
George Kaiser