I've installed the extension Magento Shipping per Product. In the admin product view, there is a text field for Shipping Rate, where you input the amount for flat rate shipping. I want it to be a select field, with options labeled for USPS flat rate, but having a value of the price. Changing this should not affect any other part of the extension, as the values will return the same information. Where should I look to do this? I've check the files and database and still no luck. I've found the setup file. Do I need to make my own file to alter the database?