Speaking as a a once-reporter...
One method that newspapers handle these sorts of situations is to use the documents as off-record assets, confirming details and running a story based on the facts within that are re-established through independent reporting. This is done with great frequency.
You can't un-know something you've seen, and you may well be able to independently corroborate this information in a clean manner. For instance, you might run a poll on CR that asks for people to give information about problems that they've had with lenses and cameras. Where you see your own data corroborating with the service memo information, you have independent information with which to follow up.
As others have mentioned, you certainly want to get advice from a lawyer who has experience dealing with fair use, trade secrets, and other relevant issues.
As a publisher, you also, of course, face a long-term issue of your relationship with the corporation that comprises the bulk of your publication's subject matter. To that issue, I'd just note that publications - web or otherwise - have tended to wither away when audiences sense that they've become captured by the interests of the corporation. My personal experience is that the reaction of a company that hates your decision to divulge something they don't wish to be divulged is very much predicated on the manner and tone with which you do it. On the other hand, when I've had business dealings with Japanese companies, I've found myself really a fish out of water, with little of my previous experience having much use.
If you would like references to law firms that have good experience about this, please contact me directly. -tig