The short answer is, No, there's not a better way.

We could tell you how to get access to the system, but there's a 99% chance that you'd regret it. Even a relatively forgiving Voicemail like Elitemail can be seriously hosed by someone who doesn't know what he's doing.

What it costs you for a certified tech (what, an hour? Two?) you'll save in not having to call a tech at overtime rates to fix the problem that happens when you're trying to fix this one. If you insist on servicing the switch yourself, in-house, get the tech to sign you up for End User Training at an NEC training Center.