Form won't maintain formatting

[SBrant]

I've created a simple certificate that has one field where people will be able to type in their own name. This form will be on the web, so I have to save it as a doc file, thus I can only use the legacy form fields. After I create the field and protect the document, the field does not retain the formating I used. When I test the form by typing in the field, the font pops from 28 pt to about 8 pt. This occurs even if I have text ("Type Your Name Here.") in the field. How do I make the field hold the formatting?