.NET Shopping Cart Dual Pricing

ASP.NET 2 CSK COMMERCE STARTER KIT shopping cart requires a new feature to be added. Products have different sizes, colors and in one order customer should be able to select same product and choose between different colours sizes and pay the right price. Currently there is a text box to enter this information manually and only one product and type (colour, size) exists. The Developer needs to modify existing code so that the product should have properties colour / size and based on each of the property a different price should be displayed. We don't want to create two product entries for the same product just because it comes in two sizes.