Change default mode of a popup

Scotty - are you trying to use a single page include for both situations?  That makes lots of sense. 

I would reccomend what Matt says above.  Write an inline JS snippet that changes the mode of the field editor based on whether there is data or not.  Existing data = read/edit mode.  No date = edit. 

I don’t think anything in the upcoming release will make this easier.  Sorry…