Very easily. Just add
Code:
$+ $chan $+


Code:
on *:TEXT:!offline on:#: {
  if ($nick isop #) {
    unset %offline. $+ $chan    
    msg $chan Offline mode Activated. 
  }
}

on *:TEXT:!setoffline*:#: {
  write -c OFFLINEMSG $+ $chan $+ .txt 
  write OFFLINEMSG $+ $chan $+ .txt  $2-
  msg # Offline Message set to: $2-
}

on *:TEXT:!offline off:#: { 
  if ($nick isop #) {
    set %offline. $+ $chan On    
    msg $chan Offline mode deactivated.
  }
}


on !*:join:#: {
  if ($($+(%,offline.,$chan),2)) { OffLine $chan }
  if ($($+(!%,offline.,$chan),2)) { return }
}



alias OffLine {
  if ((%floodhell_*) || ($($+(%,floodhell_*.,$nick),2))) { return }
  set -u30 %floodhell_* On
  set -u3600 %floodhell_*. $+ $nick 
  msg $chan $read(OFFLINEMSG $+ $chan $+ .txt ,1) 
}


on 1:OPEN:/msg # %offline. $+ $chan On


Again if you would test this that'd be great