In the admin area at Email server I filled the input From Address so the email notifications "to be sent" from firstname.lastname@example.org. I used the smtp at Send mode and I filled all the inputs with my google account but at the end the email appears to be sent from my gmail and not from the address email@example.com.
I tried also the php at Send mode but again I didn't received the email from the custom address.
I use the version:
ownCloud 9.1.5 (stable)