Moving commits from one branch to another

["Stefan Schulze" <algroth@gmx.de>]

Hi,

my team uses a central git-repo since >1500 commits and now we have to sync
(only one-way is necessary for now) our repository every three weeks with an
external svn-repo.
I created the new base-directory (incl. trunk/tags/branches) in svn and
added it to my local repo using git svn init && git fetch.
Now I have two branches in my local repository (master and "svnbranch") and
cherry-picked the very first commit from master to svnbranch (it was
probably not necessary), tagged this commit as "publishedToSvn". Now I want
to add all commits publishedToSvn..master onto svnbranch. I didn't managed
to succeed using git-rebase (probably because of the missing common
commits?) and using git grafts / filter-branch modifies my already published
master.

Is there any way to move/copy commits from one branch to another without a
common base-commit and without a forced push of master?

Thanks in advance,
  Stefan Schulze