Persist does not save props when server completely restarts even if sbox_persist is on 1

Title says it all,
my RP server seems to have a problem - It does not save props even if they become persisted. The save if i do changelevel but after i completely shutdown and restart the server, the props disappear.
YES - even with sbox_persist on to 1.

Your convar is set too late.

So i should set it in the server launcher shortcut in this case?