Hi Org,

here is a patch for master that enables the use of a custom headline
prefix file locally in conjunction with orgstruct-mode.

    2013-01-28  Christopher Schmidt  <christopher@ch.ristopher.com>

            * org.el (org-outline-regexp, org-heading-regexp): Make them safe
            local variables.
            (org-outline-regexp-bol): Remove variable, new function.  All
            users of org-outline-regexp-bol changed.
            (org-cycle-global-status, org-cycle-subtree-status): Set state
            property.
            (org-heading-components): Use org-heading-regexp in
            orgstruct-mode.
            (orgstruct-mode): Simplify docstring.
            (orgstruct-setup): Simplify implementation.  Translate keys to
            their most general equivalent.
            (orgstruct-make-binding): Generate index on the fly, discard
            alternative keys.
            (org-get-local-variables): Honour state property.
            (org-run-like-in-org-mode): Do not override variables with
            non-default values.
            (org-forward-heading-same-level): Use org-outline-regexp-bol.  Do
            not skip to parent heading.
            (org-backward-heading-same-level): Use
            org-forward-heading-same-level.