The folks are correct, you must do it in your state, which in my case was a two step process of getting it notarized by the County Clerk in the county where the state capital is located and then sent to the office where the notary is done. I called ahead of time and my mom sent an S.A.S.E. for the next office, and the notary folks were nice enough to drop it in the mail for me onto its next stop, so no one had to make the trip to the capital. But, I'm from Kentucky, and we folks just like that! : )
On another note, I recently renewed my DNI, which because I was out of the country for a year, was actually processed as a first time DNI request, "RESIDENCIA TRANMITE 1ra vez PARA MAYOR DE 16 AÑOS." When I got there with all my paperwork, including my birth certificate, they handed it right back to me and said it was unecessary. I stumbled saying that I had seen that it was required paperwork on their website, and their response was literally, "Forget about what you saw on the website." Anyone else recently told the birth certificate was not needed?
It wouldn't hurt to check at Migraciones, but it's best to do it with a
TURNO, otherwise you just get the guy at Ventanilla 7 No-Mercosur who will quickly answer your question while not looking you in the face in such a way that it leaves you wondering and worrying whether he actually answered your question or was just trying to move you along (though he probably answered your question, seems to be a nice, efficient guy who spends the day herding us around!).