Hi Maria,
Extracting transactions isn't enought to reimport them correctly:
- First you have to ensure that the definitions of both databases are the same, else it will fail,
- Second, the links between documents have to be recreated while importing: so a static query won't do the job.
I did it once for a customer in Algeria in 2009 (and have to redo it these days), and I can assure you this is not an easy task.
On that time, the company for which I did it didn't want to ear anything about addon, but by far this is a much earcier job to do by programming than by pure SQL.
Regards,
Eric