I have setup UPD's and associated them with the file/item category. These UPD's are also mapped; and in the appropriate circumstance, set to create the property. I have rules setup to auto-categorize the files to the right category. When I create an item for the file; those properties are missing their value. If I manually update the file data sheet and then create the item, the item receives the values.
My idea:
When you create/update an item, first update the data sheet then create/update the item. Then all the property info you setup is in play.