Alarms - Much better but still no 'before event' check box

Hello all,

I am very happy to see the much improved Reminders box. I still have one 
problem though. There is no check box (or any other method) to set the 
time for X before the event in question. It is only possible to set a 
time for X from now. How do I go about submitting this feature request?

Thanks
Damian