Container fields export and import

Hi

FMP13, cross platform

I have a DB that I use as a master for different clients. From time to time I make updates for them by exporting their data and importing it into the new version.

This works nicely except for the container fields. I use open external storage. When I export the data the container content gets embedded (I haven't seen any script options to keep FMP from doing that) and the export files get really big. When I import them it gets very very slow (begins fast and then slows down to like 15 seconds per record). So for 12'000 records it would probably take a day or two. 

In the end I could get the pics and docs to external again by opening the field definitions of the container fields but I can't wait for days to import the files. And maybe I would lose the pics again when I upload the DB to the server...

How can I handle this situation? It's very annoying. Obviously I don't understand the container concept well enough.

Thanks for your help and kind regards