StGIT: Trouble adding files to non-topmost patch

I keep a copy of the Eclipse source code checked out from CVS, and I use StGIT to manage both long-term and short-term local changes to the source. (StGIT is so much nicer than shuffling patches by hand!) My StGIT patch stack is based on an empty tree; the bottom-most patch (named "origin") contains the original Eclipse source and the others contain my changes. I use "cvs up" to pull updates from Eclipse's repository, a custom script to load the updates into the git index, and "stg refresh -p origin" to load them into the patch stack.

However, when the Eclipse developers create new files, I can't seem to add them to "origin" this way. After my index-updating script runs, "git status" shows that the new files have been added to the index, but "stg refresh -p origin" doesn't change "origin" and the new files show as untracked again. Some investigation revealed that the problem is that, whenever StGIT pops a patch (including as part of "stg refresh -p"), it resets the index. Here's the relevant code in git.py:

        def switch(tree_id, keep = False):
            """Switch the tree to the given id
            """
            if keep:
                # only update the index while keeping the local changes
                GRun('read-tree', tree_id).run()

This behavior doesn't affect changes and deletions since StGIT automatically adds them back to the index, but it completely controverts additions. Please provide a direct way to add files to non-topmost patches.

One could argue that my setup is bad. I could work around the problem by loading updates using a separate tree holding a clean CVS checkout, but then it is less convenient to check out additional modules. I could download and import the entire CVS history with git-cvsimport, but that would take an enormous amount of time and disk space. I'm open to practical suggestions for a better setup, but I do hope the problem with StGIT gets fixed.

[I am off-list; please include me in replies.]

Matt