Embedding a font to use it in a form

Hi,

I try to use pdfTeX to create (text field) forms, and I would like to use 
an embedded font for the text fields, instead of the standard system 
fonts.  This is feasible (Acrobat can do it), be it that the font needs to 
be embedded in full (i.e. not a subset), and apparently in a special way 
(they do not appear in the list of embedded fonts in Acrobat).

This question is more or less similar to: http://tex.stackexchange.com/questions/36630/hyperref-how-to-format-text-in-a-forms-text-field , but it got no answer.

Does anyone know how to do this?

Thanks,

Gregory