to show those fields only when Maestro is selected you would need to write a javascript function to trigger on the onChange event of the card type select list.
for the validation to happen when maestro is the selected option would also require hand coding. you would need an if statement around the validation for those fields.
the error I believe is caused by the start month format, it needs to MM
so
01
012
etc
We could help you with the hand coding in a premiere support appointment:
http://www.webassist.com/premier_request.php