Submitting Post Data Via A Redirect

A coworker is creating a form. The user fills in some numerical data. We would like to present them with a Calculate button that they can use to submit their numbers and be presented with the same information but also with the totals at the bottom. BTW, we cannot use JavaScript so it must all be done using server-side ASP.

That part is fine but we also want to provide them with a Submit button in addition to the calculate button. Now, I realize that if both buttons are contained within the same <form> tag, there can be only one action URL.

We toyed with the idea that if name=calculate, display the original form with the fields filled in and the calculations done and if name=submit, redirect to the thank you page but given that the method is post, then the redirect would not transfer the post data. If the method was get, then the redirect could include the query string data in the URL but that is not the case.