The Quantum Gateway uses the Authorize.Net gateway in Pinnacle Cart to communicate with the payment processor. To activate this gateway, simply select Authorize.Net AIM 3.1 from the gateway list and change the "URL to Gateway".
https://secure.authorize.net/gateway/transact.dll to
https://secure.quantumgateway.com/cgi/authnet_aim.php
You will fill in all other information they give you as requested by the gateway's settings in the cart. This is shown in the KB article linked below. Attached is also their PDF explaining this.
http://www.pinnaclecart.com/kb/questions/226/
