105457 Invoice Shopping Cart - Help

I have Playflow and I am trying to make a custom Invoice program. What I need done below... Here is the link to the site: [login to view URL] I want all of the (Total Price) fields to be calculated and the total for all placed in the (Total Sale Amount) Field. Then the info must be carried over during the credit card checkout and at the end I need a reciept page to come up so a reciept can be printed for the total sale and info.. EASY. I can't figure it out. I use Verisign Playflow