[Plugin: eShop] Adding a new merchant gateway

This isn’t really for the developers of this plugin — because I know you’re very busy, too add every single gateway available — but more for anyone who has been able to add a new gateway to the plugin.

I’m looking to add CardSave via their redirect / hosted method;

http://www.cardsave.net/Workwithus/DeveloperSupport/IntegrationMethods/RedirectHosted.aspx

which from what I can see, should be similar to what eShop does with current gateways; shopping cart on WordPress site – then sends request for payment to gateway and waits for a return saying payment was OK or not.

Does anyone have any experience or tips to share please?!