Gary,
I think that you'll have to do this on the Acrobat side by embedding a javascript routine in your form(s).
There's an overview tutorial at AcrobatUsers on using Javascript with Forms, see: http://acrobatusers.com/tutorials/using-acrobat-javascript-with-forms
IIRC, you'll need to create a "Document Level Script" (see: http://acrobatusers.com/tutorials/js_document_scripts) that contains:
// reset the form
this.resetForm();
For more PDF scripting tips, check out Thom Parker's PDF scripting site: http://www.pdfscripting.com/public/main.cfm