How to use a dynamic URL to receive Paypal notifications?

Question

So, I know it’s possible to set a notification URL through the client area, and I also know that you need to activate the notification feature.

However, I need to define the notification URL at the time I request it, how can I do this?

I turned the Paypal documentation and found a few quotes that talked about such a possibility, however, at no time they explained clearly how to do.

The page with more details I found was this (at the end): https://developer.paypal.com/docs/classic/ipn/integration-guide/IPNSetup/

With that, I did the following (it’s just a piece of code):

$nvp['PAYMENTREQUEST_0_CURRENCYCODE'] = $responseNvp['PAYMENTREQUEST_0_CURRENCYCODE'];
$nvp['SUBJECT'] = $responseNvp['SUBJECT'];
$nvp['METHOD'] = 'DoExpressCheckoutPayment';
$nvp['NOTIFYURL'] = 'https://dashboard-clayderson.c9users.io/notify-url.php';
$nvp['PAYMENTREQUEST_0_PAYMENTACTION'] = 'SALE'; 

Didn’t work.

I also tried Setexpresscheckout and it didn’t work. They can give me a light?

Detail: there is no way there is a problem on the page that will receive the notification, because right in the first line I had it recorded in a file. txt all hits the page, and had none, besides, I used IPN Simulator and managed to capture the data perfectly.