How to convert User Defined Table text to date in BI Publisher

Hello

I'm trying to work with a User-Defined Table (UDT) and am running into reporting issues working with the data in BI Publisher and am looking for help. 

The business need is that we want to create a table that stores integer codes with their associated effective start and end dates. However, we want to be able to give future values to the effective-end-dates in the UDT. This is not how UDTs work, though: when you end date them in the UI, they can only be end-dated with the current date and you have no option to change that effective end date to a date in the future.