Is this easy to do ?

I have a site still running on ASP built with E cart . I want to be able to add one of 4 new Carriage
Charges for home deliveries ( So I guess these go under Shipping Charges )

The site works as follows

First you add an item to the cart here ( for example )

http://www.rosewoodfurniture.co.uk/rosewood-furniture-cartpay.asp/product/ff7318p-ming-style-curio-cabinet

You are then directed to see your cart contents here

http://www.rosewoodfurniture.co.uk/rosewood-furniture-uk-cartnew.asp

I would like to be able to add a LINK on this page to a new page I have made ( below ) where clients
can then select a White Glove home delivery at a SET price to the cart

http://www.rosewoodfurniture.co.uk/rosewood-furniture-white-glove-delivery.htm

Options are

1. Zone 1 2 3 Uninsured Home Delivery - This will add a value of £108 to the Cart

2. Zone 4 , 5 Uninsured Home Delivery - This will add a value of £144 to the Cart

3. Zone 1 2 3 Insured Home Delivery - This will add a value of £145.20 to the Cart

4. Zone 4 , 5 Insured Home Delivery - This will add a value of £181.20 to the Cart

I really dont want to have to break open the cart as I dont have the old version of E cart installed.

I just need some code to add to each of the 4 buttons which will allow the user to Add one of these 4 fixed
amounts of money to the shopping cart under shipping charges

What is the string of code I need please to add one of these Static Amounts to my Cart after the product
has been added


Hope you can help

Thanks in anticipation


John