Page extension doesn't show up in TeamCity 4.5

I'm in the middle of adding a page extension to my TCGrowl plugin (http://code.google.com/p/tcgrowl/).  It works fine TC 4.0.2, but when I try it in 4.5 my extension doesn't appear (but the other part of the plugin works fine).  Do I need to change something to get it work in 4.5?  I'm trying to place the extension at PlaceId.NOTIFIER_SETTINGS_FRAGMENT.

You can see the code here: http://code.google.com/p/tcgrowl/source/browse/#svn/trunk/src/net/slimeslurp/tcgrowl

Thanks!