[pdftex] how to use TeX fonts into a PDF Form

[Juan I. Montijano]

I would like to do a Form (using \TextField macro of hyperref package) 
in which the value can be written in a TeX font.  By default Helv font 
is used, and I know how to change it to an other acrobat font, for 
example, by setting the font in javascript code 
this.getField("...").textFont=font;

The point is: can I set the font to one of the TeX subsetted fonts that 
are used by the document (cmr10, etc.) ?
I have found the pdftex primitives  \pdffontname and \pdffontobjnum, but 
I don't know how could I use them.

Regards,
Juan Ignacio
-- 

+ Juan I. Montijano 
   Dept. Matemática Aplicada
   Edificio de Matemáticas
   Universidad de Zaragoza
   50009 Zaragoza (Spain)
( +34 976 761120 FAX: +34 976 761125