Clock Menu Extra Time Format

I recently received my copy of Snow Leopard and installed it from scratch (erase and install, essentially). It works well for me, however I am consistently trying to figure out how to change the format of the clock menu extra (upper-right of menu bar). I am able to change the time formats in the International/Language and Text/whateverit'scalled preference pane, but it is not reflected in the menu extra (eg "12:31" to "12h31").

Switching the menu extra to analog and viewing its menu reveals the time in the format I want it in. I have tried manually editing this format in the com.apple.menuextra.clock.plist file but am unable have my changes stick when I restart the SystemUIServer application. It always reverts back to "H:mm". Changing it to "E H.mm a" will result in "E H:mm a" so some parsing is taking place.

Attempting to change the format to something a little more trivial like "12.31" does not work unless I switch the locale to Norway (possibly not the only one). Others like Hindu, which have a totally different writing script, change the the menu extra to reflect that script—so it's not completely limited to #:##—however the com.apple.menuextra.clock.plist remains "H:mm".

This use to work without too much headache in 10.5 and before, but now it does not. Any help is appreciated.