To add the CVV2 Number area to the default credit card payment module, please follow these steps:

A. Make a back-up of you store:
Although optional it is highly recommended that you backup your files and database before proceeding. For instructions on how to make a back-up of your store, please refer to Back-up Commerce Pro store

B. Download appropriate contribution from oscommerce website and follow documented instructions included with the download:

http://www.oscommerce.com/community?contributions=&search=cvv2&category=all

NOTE: Contributions are provided by the community in the form of project add-ons, feature updates, language packs, and extended modules. Support for the contributions are not provided; however you may post questions to the oscommerce forum at: http://forums.oscommerce.com/