Order of PDF Package Files

I'm attempting to arrange the files in a PDF Package in a specific order yet no matter what I do in the DDX it they still get sorted alphabetically.

This is a simple example of what I want to do;


   
    
      
      
    
   


When the package is displayed Doc1 shows first then Doc2 rather than the order shown in the DDX.

Does anyone have any idea how to create a non-alphabetic order of Package files.