Wordpress digital download price integration on paypal buy now button

General information for the website: a digital download sale on wordpress blog
Kind of development: Customization of existing website
Description of every page/module:









<a href="



Price: &#36;

<form action="
QTY:

<input type="hidden" name="wppp_product_id" value="










inside the zipped attachment there is checkout.php where the product price is been called on the line:

21. $paymentAmount="9"

I am looking to the price automatic by using the meta_value [product_info_price] from the worpress template above and also make it possible to loop for all product in the cart. I do believe it will need to make this a cart.

I wanna make it possible to redirect client to a page where all the purchased download file will be available. At this point the app only works with one downloadable product .
Description of requirements/features: php syntax issue
Extra services needed: Customization, 3rd party integration
Specific technologies required: paypal IPN and API and wordpress
Extra notes: to can get an idea from this http://jmsliu.com/1307/integrate-paypal-digital-goods-express-checkout-into-website.html#comment-95056 where I bough the plugin or script