Nearly all payment gateways can be setup to collect credit card data by posting to them a form created of hidden fields. In this case the secure pages are hosted on their server and they simply require details about the order. The payment gateway may or may not return information to the cart as to whether the the customer's card was accepted.
If you want to try to setup a gateway using this option then you MUST read the gateway's documentation very carefully and make sure you understand it! Furthermore, we make no guarantee that it will work with all gateways. In other words it must be compatible with the principles used here.
Click here for more information on setting up the Custom gateway...
URL to this page: https://www.mals-e.com/tpv.php?tp=18