Hacking Transferring all data from old 3DS to New 3DS?

[bache]

I've bought a New 3DS and am now selling my old 3DS which is Gateway compatible to a friend. The friend has to take it now, and he lives interstate and is leaving tomorrow. I've backed up all of my saves using SaveDataFiler, so there's no issue there, but I would like to transfer my Nintendo Network ID to my new console, when Gateway and emuNAND is available for the new console. It's my understanding that to use the transfer tool, I'd have to be on the newest firmware on both machines, which is obviously not going to happen. I've read that you can call Nintendo after the device has left your possession, and they can manually remove it from the old machine, so you can link it to the new one. Will this retain my eShop purchases? Is there another way to go about this?