I'm not 100% but as far as I can tell you need to unlock with something like Wotan. I've looked around briefly and that's the general consensus.
In any event using Wotan is not that difficult and the only downside is you have to pony up some $. Still way less than you would pay at an local unlocking store though... just my 2 cents.
Unless anyone else can provide insight on a totally free solution I think you're best bet is Wotan
EDIT: Do a search on this forum. After i posted this i did a quick search to verify my thoughts and I stand corrected. There is a free method.