I found it somewhere and it worked on my latest trial version of ESET Nod32. Not yet tested on Smart Security. It locks up the trial to 31 Days just like the Box MaraFix did. I don't know who made this one but I'm sure it'll work for you. ^^
Available for users only
Install trial version ESET Nod32 or Smart Security
Press F5 to bring up options
Deselect 'Enable Self-defense'
Restart and apply patch 'ESET Fix X.XX'
Press F5 and reselect 'Enable Self-defense'
Restart once more