You can, but you would have to do the integration for the actual payment following their documentation directly.
This is something we can help you with in a premier ticket as well. It usually can be done in an hour or two depending on how well the payment gateway documentation is written and the example available.
I'd suggest using authorize.net when running the eCart checkout wizard and then you would just update the authorize.net checkout code to use the new payment gateway. It would just be one section of code on the confirm.php page.