How to make persist a change of esxi5 firewall

I want make persist  change firewall for open smtp port.
I have copied smtp.xml  on persist datastore (es. /vmfs/volumes/datastore1) under directory script.
Now i have change the rc.local file whith :

/bin/cp /vmfs/volumes/datastore1/script/smtp.xml /etc/vmware/firewall/smtp.xml
esxcli network firewall refresh


Bye