How to use unicode values in form fields
An easy way to use unicode values is to instruct the reader application to re-render all field appearances at viewing time. This is done by calling the setNeedAppearances()-method of the FormFiller instance.
Common applications like Adobe Reader or Acrobat will automatically create the field appearance then.
It is also possible to provide an external font file which will be used for the rendering process. Just check this demo for more details.