How to change home directories volume ?

Hello

It seems that ReadyNas use the first volume created to host home directories.

I search how to change the volume on the internet

I found that i have to change in /lib/systemd/system/home.mount

[Mount]
What=/SECURED_DATA/home

It seems to work after reboot. Files are now hosted on the new volume however

In the GUI, it still appears on the old volume.

In the db, i found the table "account_default" which to contains the information.

I changed it and it worked but only during current runtime !

After reboot, the "home folders" are back on the old volume in the gui

How to change it forever ? 

Thanks for your help.

Regards