You'll need to determine your Gateway Merchant ID and a Gateway Merchant Key. Contact Sage's support if you have difficulty determining these values.
To complete transactions in FoxyCart using the Sagepayments.com Test Server, you will need to use test credit card numbers provided by Sage (instead of real ones). Test credit card numbers listed on the Sage Developer site:
A test value of “123” should work for the Verification Code.
Sage Payments is only supported by FoxyCart v040+.