We would like to remind you about payment application security mandates from VISA.
New payment application security mandates require Visa clients to use, and ensure that their merchants and agents use, payment applications that adhere to the Payment Card Industry Payment Application Data Security Standard (PA-DSS). These security mandates require full compliance by July 1, 2012 for all regions and merchants. Deadline for US merchants was July the 1st 2010.
Simply put if you host credit card payment form on your web-site you are to use a PA-DSS certified software to process credit card payments.
You can use X-Payments - a PA-DSS certified payment software - to process payments for your X-Cart shops and thus meet the requirement.
Please do not hesitate to contact us should you require any help with getting your X-Payments license working for you.