Problems with Kali Persistence

Hello forum!

I need some help with kali persistence. I already succesfully setup a live boot usb with encrypted persistence with Kali Linux 1.1.0, but now that I passed to 2.0.0 I'm having a problem. The partition is encrypted and asks me for the password but nothing I do is saved, neither the options nor files. I simply followed these steps:

The only difference was that instead of using

echo "/ union" > /mnt/my_usb/persistence.conf

that gave me "Permission denied", I used:

sudo sh -c "echo "/ union" > persistence.conf

as I read in another guide for someone who had the same problem. Don't know why, but it worked for 1.1 and thought it would be the same. I noticed that this time the partition "persistence" is completely empty and can't find persistence.conf anywhere.

Thanks in advance for your help!