There are a few differant ways to make a buff for 097, your not limited to just one way as in v1.x

here is two such examples:
1).
$session['bufflist']['106'] = array("name"=>"`#True Warrior","rounds"=>12,"wearoff"=>"You sober up from the frenzy.","defmod"=>1.3,"atkmod"=>1.4,"roundmsg"=>"Your spirit is frenzied in battle.","activate"=>"defense");
2).
$buff = array("name"=>"`^Dwarf Grog","rounds"=>20,"wearoff"=>"`!Your Dwarf Grog buzz fades and sobriety returns", "defmod"=>1.5,"atkmod"=>1.3,"roundmsg"=>"You feel good!","activate"=>"defense");
   $session['bufflist']['magicweak'] = $buff;

If you need any further help with 097 backdating, just ask.