git-svn: add/obey a hooks/prepare-commit-msg

First, thanks for git-svn!

I'm trying to make a edit to the log message when pulling
from SVN into GIT using git-svn.

It's going bidirectionally, so I don't want to
git-filter-branch.

I tried creating a hooks/prepare-commit-msg script; it works
ok when manually doing a "git-commit" but seems to be
ignored by "git-svn fetch".  I made a hacked-up copy of
git-svn that edits the log message the way I want and it all
seems to work.

Can support for obeying commit-msg hooks be added to
git-svn?  Or, is there another way to do this?

Thanks!