Ok, in case it helps anyone, here is my experience. I did not call anyone.
My old Pre3 was kept on airplane mode.
I had accidentally activated my new one on a second profile I had made for testing and that had erased my old profile on my normal account.
I did as follows:
1. Full Erased the new Pre3 to clean it up.
2. Erase the profile from the testing account. Now I have no profile of my Pre3s anywhere stored (ARGGHH!!!)
3. Take the old Pre3 from airport mode. When it asks to erase it, say no, that you want to reuse it (Sorry, I forgot to take a screenshot, I was kind of stressed at the time )
4. The Pre3 is going to reboot! Let it be.
5. When it reboots, it will ask you to sign in or create a new account. I just signed it in to my account. After it signs up It wil ask to verify all accounts.
6. Back it Up
7. Turn airplane mode again. After that I think I have a full backup again and all my apps and data.
Now I can proceed to activate the new Pre3 on this account and migrate it all to it.
My old Pre3 is kept on airplane mode now just in case
I read it. But it does not quite help in some cases like mine.
For starters, it assumes that you have a working profile with the HP servers. On my case I had accidentally erased it.
And if I took the old phone to the net, it would be erased as soon as it contacted the HP servers.
I think we need also an offline solution for cloning/migrating one's phone.
That's correct.. for activation (at least GSM phones) you need a SIM with mobile data connection. You can skip the activation and set up Wifi. Not sure if you can create a new palm-prolfe after that on device. Maybe impostah can do also that..