I would like to add a payment option to Magento 1.6.2 that allows customers to choose to pay by bank transfer. I see there is at least one module that will offer this functionality (http://www.magentocommerce.com/magento-connect/bankpayment.html), but I also need to apply a discount to the cart total if Bank transfer is selected as the payment option. Does anyone know how I might achieve this? I am thinking that automatically applying a discount "shopping cart price rule" to the cart if bank payment is selected might work, but it must not be applied to other payment options, and if the customer changes their mind on payment option, it should remove that discount, etc.
Any ideas/pointers greatly appreciated. Cheers!