I'd like to suggest to track history for BOTH "halves" of file when it is refactored to be splitted. For example, when you "move class to upper level", "extract superclass", "extract interface" etc. Now one such part is marked as "modified" and another one as simply "added" (without history). Now I have to do extra actions to achieve that result. To be specific - when extracting MyInterface from MyClass:
1) refuse to add MyInterface.java to svn;
2) rename MyInterface.java MyInterface.java.0;
3) svn cp MyClass.java MyInterface.java;
4) move MyInterface.java.0 MyInterface.java.