Bottling or kegging date is actually controlled by the fermentation profile. You cannot enter in the date directly, but if you adjust the fermentation profile based upon the actual number of days in the fermenter the date will be reflected in the calendar appropriately. What you are looking for may be a nice feature to have added in the future though. I track bottling/kegging dates as well, but rarely go back and made the necessary adjustment to get the program to align with reality. Like all estimated values in the program which allow for user input of actual readings, this might be a very good variable to track for brewers.