Good Afternoon,
"I think that you want to set an alarm time from user input and to have the alarm trigger once. Is that right ?"
More or less, better ...
I want to set an alarm time from user input and to have the "Alarm TriggerOnce" each time that the user input match the trigger ...
So for example:
- Call Timer1 ---> for start at 15:00 28/01/2013
and Can call Timer 1 each time base on the user input ...
If put Alarm TriggerOnce(); into the setup will be excute only one time or every time that value will change ? (of course behind the of value MakeTime() will change )
It is more clear now ? 
Thansk 1000 for the support,
gnux