Conference Registration Form

I have a conference registration form and confirmation page designed in FP2003. I have 3 things that I need help with. (1) I need the html coding fixed so that it calculates totals on the registration form. The data, then is displayed on the confirmation page. (2) I'd like to have the ability for the user to go back to the registration form to correct errors without needing to re-enter all of the data again and to have the corrected data displayed on the confirmation page. (3) I need certain fields to carry over to the payment processing page so they don't need to be entered manually (like company name, total dollars from the registration page, etc.) (Payments are not processed automatically but credit card information is submitted to a secure server where it is processed manually.)