Exporting and importing personal bookmarks in SAC

Hello everyone!

I would like to ask if any of you have any knowledge about exporting and importing personal books in SAC Stories?

The situation is that we have a Story in which many users have their own personal bookmarks, but they have to switch to the new version of Story (different ID). We want to avoid producing bookmarks from users from the beginning.

I tried to dig in the .tgz file (original Story) in which I found them and then pasted them into a new .tgz file (changing the target ID and adding bookmarks to the object file) which will be the final version of the new Story. Unfortunately, when importing a file, I get an "Illegal file" error.

Is there any way to fix this error? Maybe I missed some important step in adding these bookmarks in .tgz file (there is not much knowledge about this). Are there any easy ways to export and import personal bookmarks in SAC?

Thank you in advance for your response.