My payment method is not in the checkout process of shopping cart, why?

First of all, please check if the payment method is enabled in: CMSDesk -> Tools-> E-commerce -> Configuration -> Payment methods -> <edit> -> Enabled: checked
Then the payment method needs to be assigned to appropriate shipping options. Please check if your payment method is enabled in: CMSDesk -> Tools-> E-commerce -> Configuration -> Shipping options -> <edit> -> Payment methods tab