Under Canadian law, we have established a president on the matter. An IP address alone from a pool of peers is not sufficient information to be able to lay any sort of charge or claim, or otherwise get any sort of court order for customer information for one simple reason… While an IP address may identify the subscriber to the internet service, this does not absolutely mean that the subscriber of the internet service was the end-user of the device that performed the infringing actions. Such is often the case with a shared WiFi network, or in homes with multiple family members. You will only have one registered subscriber, however there can be any number of people whom could have been using the service.
My best advice would be to refer to a lawyer to see about the applicable laws and options available for your country.