You can only supply time in hours/minutes in the timer.
You can however do something like this, scripting the date check yourself:

alias timedstuff {
if ($date(yyyymmdd) !isnum 20050630) {
; below test only to not have the timer activated if the date has already passed
if ($v1 > $v2) return
.timer 1 120 .timer $time(HH:nn) 1 1 timedstuff
return
}
;do your stuff
}

Yes, there's 2 timers in there, otherwise you'll be setting a timer every 1 or 2 seconds until it's one minute later.