Setup within Kartris | Kartris User Guide

Go to Configuration > Payment and Shipping Gateways and click to edit Netbanx.
For 'friendly name', you can enter 'Netbanx', 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 Netbanx payment page 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 Netbanx payment process.
Rather than having an account ID to identify your orders to Netbanx, it has customized payment URLs that include your site or company name. There are both test and live URLs, with the format as follows:

https://pay.netbanx.com/OPsite-name-upp
https://pay.test.netbanx.com/OPsite-name-upp

Kartris will decide which one to use based on the STATUS setting for this gateway.