Hello all, fixing some bugs I have published a new version of the package org-refer-by-number to Worg:
http://orgmode.org/worg/org-contrib/index.html ,where it available as a contributed package. The location of the elisp file is: http://ferntreffer.de/elisp/org-refer-by-number.elThe file is documented extensively, so I hope the package can be used readily by anyone, who finds it useful.
regards, Marc-Oliver Ihm