I found that allow past date = 0 will prevent accepting the date in the past.
Use an external task. Call a PERL Script which can read the metadata from file and validate accordingly.
Cant we write events for Save & Save&Close buttons on Tag File. Can you please confirm? The workflows i dont have much knowledge i am using existing workflow.
Can we write some method like onblur or something in text item. Now on call out it is handling past dates validation correctly. Same thing cant we do it?