Please put your salesletter here by editing the file /html/product.html. You can customize the position of where the paypal and stormpay buttons are displayed by putting the tags "(PAYPAL-BUTTON-HERE)" and "(STORMPAY-BUTTON-HERE)" where you want the buttons to appear. (replacing ( with [ and ) with ].

[PAYPAL-BUTTON-HERE]

[STORMPAY-BUTTON-HERE]