buy now single product checkout PLEASE HELP

hi guys , i love opencart but i really need a buy now ! single product checkout
ive searched the site but didnt found any , is there any way to modify a normal chechout (in a simple way )
maybe just 2 ignore the cart & add a buy now button

or if somebody is kind enough 2 provide me with the scripts necessary

i need it for some downloadable products , as simple as possible , i just need a button for single product express checkout, i need it 2 ignore other products in the basket but no empty the basket, the order confirmation in the admin panel , & of course the same option for download  , i home i didnt missed anything important

i am offering downloadable products via a SMS(by mobile phone) payment gateway & my problem is that at the curent setings customers can checkout with as many products as they want


my curent gateway sistem starts from cod.php

"
return $method_data;
  }

  function getActionUrl() {
    return $this->url->ssl('first gateway page.htm');       -> second gatewaypage.php
"


then it simply redirects to checkout
.......................................................................................
i am accessing the cart thro an iframe  & after the payment is done it bounces me out of the iframe & the checkout_success page opens directly
maybe any of u can give me an idea how 2 solve this problem 2



THANK U VERY MUCH & I PROMISE 2 RETURN THE FAVOR ANYWAY I CAN

I am working on a Paypal Express addon, which I assume is what you are after.

The addon will allow checkout from
A) the product page
B) the cart page
C) the checkout page

I hope to be done with it in about 2 weeks

no i dont need it for paypal , i just need something like what it is in the cod.php file , but with what ive mentioned above , i did a few edidting in the files to enable it 2 work as it doesa now , but even this took me an extremly long time , coz i dont know PHP , or java as a matter of fact, still i'm learning , ive asked 4 this help as a last resort

it would be great if u could modify this files for an express checkout

thank u

Well since the customer would need to be logged in for that to work, it seems moot. Paypal Express would handle the login and address for you so it makes sense that way. But if you just want COD express, you'd need to have the customer log in anyway. So for them to click to goto checkout_success or click to goto cart->checkout_confirm->checkout_success makes a lot of confusing work for the store and the customer.

i am not sure i really understood what u wanted 2 say , but the thing is :

yes i have my customets loged, coz the will get the products from they account page->downloads

i need a link from the product's page 2 jump directly 2 a file similar 2 cod, ( not cod coz i'm also using that ) from here i redirect the customer 2 the payment gateway , & i return him to process page  witch i think it needs 2 be modified 2 procees only that product

(& the cod file 2 foward onlly that product & ignore the rest of the cart, (just ignore, not delete) )

i apologise if i made any mistakes , but this is the curent level of understanding about how the script in this cart works, that ive managed to achive by miself 


thank u