File modification and the copyright

[T o n g <mlist4suntong@yahoo.com>]

Hi, 

If I take a simple file (BSD-licensed), (greatly) improved it, and 
include it in my package. How should I handle the situation? 

- I should claim that the author of the new file is me, right?
- I should inherit the BSD-licensed, right?
- How to express that the new file was based on another old file from a 
different author in the debian/copyright file?

Thanks