I'm pretty sure that it has something to do with the spread ids. I've never looked into it, but might it be the numbers in hex format?
Thanks Harbs, I need this clarification to modify the InDesign files using the IDML files, anyone pl. give further details on this?
Check the id of a few spreads, export to IDML, and compare the
suffixes. I'm sure you can figure out the pattern. When you do, you
can let us know...
I done this exercise, but it's not matching.