E-Commerce Configuration Guide : Site Configuration Settings : Item Settings : NoItemDateText
 
NoItemDateText
Key value:
Any text
Description:
Displays a message below the calendar if at first no date is selected from the ItemList.aspx page and the NoDefDate is set to 1. Sets the text to display in place of the date.
Example:
NoItemDateText = Please select a date!
See also:
NoDefDate