Setup within Kartris | Kartris User Guide

Go to Configuration > Payment and Shipping Gateways and click to edit Secure Trading.
For 'friendly name', you can enter 'Secure Trading', or just simply 'Credit Card'. This is just the name of the payment method that customers will get to choose on the web site during checkout if you have multiple payment methods.
Change the status from 'OFF' to 'ON' (for live orders) or 'TEST' or 'FAKE' for testing. 'TEST' invokes a demo order, allowing you to test the full integration and pass multiple orders at zero cost without needing to do refunds. 'FAKE' means that Kartris will skip the Secure Trading site and instead format a post back itself to the callback page of Kartris. This is useful for testing that the callback process works, triggers the appropriate emails and so on without keep having to keep going through the Secure Trading payment process.
'Required Fields' should be set to 'name,email'.
'CallbackID' should be set to 1 if you only have a single web site. If you use your Secure Trading account with multiple web sites, you can number each of them.
'SiteReferenceID' should be set to the values provided by Secure Trading.
'Password' is an arbitrary password you use to protect the callback process; it should match the one set up in the callback.txt file (see @17.19.2. Setup within Secure Trading).