DVDit! 5 and 6 has the ability to open projects created in MyDVD (version 5 and higher).
To do this, just select File -->Open. Then select Sonic DVD Projectfrom the Files of Type pulldown at the bottom of the Open File window. This will enable DVDit! to recognize MyDVD projects.
Once a MyDVD project has been selected, it can be edited and adjusted as DVDit! project.