I created a new version of Xournal with Notes-import functionality. See the new menu entry File->import Notes. I am not sure if the scaling is OK on a DR800, I only have a DR1000. I also made some changes for importing annotations for large pdf files, but there are still problems (I hope I did not create regression in the exsisting functionality).
Please let me know what you think of it.
The update is available in the FIRST POST OF THIS THREAD