Allow us to select a date for a task before a Key Date.

I have several "Key Dates" Task that happens before the Key Date. It would be great to be able to select "days before" or "days after" for these tasks. As if the date is changed, I then have to go in a find all the tasks associated with the one Key Date, before the date and change it too. It seems silly to even have the Key Date option with out having to have tasks before the date as well.