on *:open:*:?:if ($away) msg $nick I'm away ...
You can use levels and give the user a level after message you, then remove the level with a timer, dont know if this is what you looking for.
;------------ EDIT
on *:open:*:?: {
if ($level($address($nick,3) != norep)) && ($away) msg $nick I'm away ...
.auser norep $address($nick,3)
.timer 1 60 .ruser $address($nick,3)
}
Maybe can be done in a bether way, but this is what i come up with for the moment.