Sorry, I forgot the source of the information.
A letter from the Sabres lawyer (or a warrant from the FBI) should take care of getting the IP and e-mail information of the poster. Reporting it to the Sabres was a good move, however I probably would not have sent it to "Contact Us" at Sabres.com. It is usually just sent to a webmaster (and not the Sabres) and may not be addressed in a timely fashion. A call directly to the Sabres front offices would stand a better chance of quick action. Just my opinion.
It is something that should be taken very seriously and a call to a live person would put the wheels in motion faster. If you do not have the number for the front office, you could probably call their ticket office, explain the situation and get a number to their front office. From there, they could direct you to the right person.