I think that the behaviour you're seeing is as intended. I haven't
played around with the bundle bit, buts its possible that you can
set this to get the bundle recognized as such. My quick test
indicated that its rarely set, at least on .app's. The docs imply
that its only valid for files in any case, which would account for
that, and rule out it's use in your case.
You've fallen for a misleading bit of outdated information there:
The Bundle Bit used to indicate whether a *file* contained a BNDL
resource (roughly equivalent to the CFBundleDocumentTypes array in
today's Info.plists). That's why it was originally documented as only
suitable for files.
However, if you set it on a folder, it will there indicate that
this folder is actually a file package, or "bundle" as it is
sometimes called. This is a new usage introduced with OS 9, which is
why there's still lots of docs out there that claim differently.
