Shouldn't git-am be able to pass -b to git-mailinfo?

Hi,

I've been wondering: git-am can pass -k to git-mailinfo, but not -b. It's thus impossible to preserve a commitmsg starting with a bracketed text.

Consider a commitmsg starting with '[ISSUE-1234] Fix breakage in XY.' git format-patch produces:

    ...
    Subject: [PATCH] [ISSUE-1234] Fix breakage in XY.
    ...

Applying this patch using git-am results in commit message starting either with

    Fix breakage...

or, using git-am -k, with

    [PATCH] [ISSUE-1234] Fix...

However, there is no way to get the original commit message using git-am's interface. Or am I missing something?

I'd supply a patch straight away, however, I can't think of a long version of -b option to go well with -k/--keep. Any ideas?