Copyright, new branches etc

[Ralph Little]

Hi,
Sorry, some more coding questions. I've made quite a few mods to about 
30 or so files and created a few of my own in my local git pull of 
Lilypond. It occurs to me that I should start doing it properly now ;)

Should I get permission to create a new branch?

For new files, what is the situation with copyright messages?
Do I put myself or Han-Wen/Jan.
Also, should I extend the copyright period to 2007 for files that I am 
modifying?

Any other things that I should be aware of?

Cheers,
Ralph