git-svn: Handling of branches created from subfolders

Hello,

I’m trying to do a one-time conversion of a large SVN repository to git using git-svn. Unfortunately, this SVN repo contains a substantial amount of non-standard branches created from a subfolder of trunk/. Users that only need to work on part of the code inside the repo usually create such branches to avoid having to download unneeded files.

A toy example showing what I’m talking about:

trunk/
    - subfolder1/
        - …
    - subfolder2/
        - …
branches/
    - branch1/ (initially cp’ed from trunk/subfolder1)
        - …
    - branch2/ (initially cp’ed from trunk/subfolder2)
        - …
    - branch3/ (initially cp’ed from trunk)
        - …

While in my experience, git-svn is able to correctly handle branches/branch3, it fails on branch1 and branch2. By "fails" I mean that it still performs the conversion, but any relationship to the trunk is completely missing. Instead, in the resulting git repository it looks like those branches have a completely separate history, starting from nothing.

Is there any way to fix such branches from subfolders in a way that they integrate correctly with the converted git repository, without losing any (or at least too much) history? If this is not possible with git-svn directly, maybe I could prepare the SVN repo or post-process the converted git repository somehow?

Thanks!