magento redirect checkout payment to a 3rd party gateway like direcpay payment gateway

Actually i am working on magento version 1.5 and i have created a payment module manually.I have enable it from the magento admin panel i.e System>Configuration>Payment Methods and i here i can see my payment module and make it enabled -> yes,so that only this module will work during payment prodedure.Now during payment information while checkout in magento frontend when i click on Place Order button in ma开发者_如何学Pythongento frontend during payment procedure it gave me a popup message "inavlid bankid" and i stuck around here,i want to know where is the landing page after this.Actually i am in the testing phase of magento and after that i want to redirect checkout payment to a 3rd party gateway Can anyone tell my how it will be done~!