[rt-users] Add a new CustomField Type?

[Kaare Rasmussen]

Is it easy to add a new CustomField Type?
I'd like to add a custom date field, but the closest I can get with standard 
RT seems to be a "Enter one value" which translates to text only. 

Steps includes
 - Add a new entry "Enter one date value" to $CustomFieldObj->TypeComposite. 
How is this done?
 - Add a new Elements/EditCustomFieldDate. How do I add all functionality for 
a date field? RT can handle smart values like 'now'.
 - What else? 

Is it a completely wrong way to get date validation for a custom type?