[hibernate-dev] Pleas help with GITHub, how to get new branches into personal fork?

[Demetz, Guenther]

Hello hibernate developers,

I want to open a JIRA-Issue and as always I like to provide an according  test-case in form of a pull-request.
I already created pull-requests in past, but now I need  to update/align my fork of hibernate-orm with branch 4.2 which at the time of fork-creation did not exist yet.
How to do that without destroying my fork first?
It seems that GitHub does allow maximal one fork per repository. I tried almost everything imaginable without success.
If someone could give me an advice please..

thanks
Guenther Demetz