I could find no way to make the feature work, so I have pulled it from the code. I have also inserted asserts to warn library users who would attempt to use illegal characters in user defaults keys in the future. In short, you want your user defaults keys to be something identifier-like.
The NSAccessibilityPriorityKey symbol was only introduced in 10.9, so that we have to check for its availability before using it, otherwise we get a SIGSEGV.
See #60 for a discussion. In short, keyCodeStringForKeyEquivalent should be now correct even with non-ASCII keyboard layouts such as Russian.