From In-Portal User Manual

Gateway

On this tab, the administrator can select which gateway to use for processing the payments of this type. The dropdown contains all payment gateways supported by the current version of In-commerce.
If ‘none’ is selected, the payment type is considered manual – the administrator is responsible to receive the payment through means outside of In-commerce. If a gateway is selected, its configuration fields will be displayed and required to be filled out.

Authorize.Net

For Authorize.net gateway (<a href="http://www.authorizenet.com/" target="_blank" label="external">http://www.authorizenet.com/</a>), the following fields are required:

• Gateway URL – the URL of the Authorize.net service, usually <a href="https://secure.authorize.net/gateway/transact.dll" target="_blank" label="external">https://secure.authorize.net/gateway/transact.dll</a>
• Authorize.net User Name – this should have been given to you when you signed up with Authorize.net or one of their resellers. It is the same user name that you might use to log into your online merchant center.
• Authorize.net Transaction Key – this key can be retrieved from the Authorize.net online merchant center at <a href="https://secure.authorize.net/" target="_blank" label="external">https://secure.authorize.net/</a>. For more information, please contact Authorize.net support.

PayPal

For PayPal gateway (<a href="http://www.paypal.com/" label="external">http://www.paypal.com/</a>), the following fields are required:

• Username – usually this is your PayPal email address.
• Gateway URL – the URL of the PayPal gateway.
• Payment Currency Code – the code of the currency your PayPal account is setup to receive.