Result url for payment plugin

[Aquatarion]

At the moment I'm writing a plugin for one of the payment system. And one of the parameters is the url where the data will be sent by the result of the payment. These data must be processed by functions plgVmOnPaymentNotification or plgVmOnPaymentResponseReceived of that plugin. What do I need to specify a url for this?

It's <url_shop>/index.php?option=com_virtuemart&task=notify
or <url_shop>/plugins/vmpayment/paypal/paypal.php
or some else... I don't know.

Thanks in advance for your reply