OK, I'm stumped.
I have a Java tree that looks like a fairly typical Eclipse Java build:
myproject
  src
    com
      example
        test
          // Java files in com.example.test here
  bin
    com
      example
        test
          // Compiled class files will go here
Now I have a MyClass.properties file in myproject/src/com/example/test along with the source Java files. How can I write an appropriate ant task to copy all the changed .properties files in the source tree, to their corresponding places in the build (myproject/bin) tree? 
(The easier half of this is to do the actual copy; the harder half of this I'm guessing is checking for dependencies)