Firefox: Bookmark creation Event

[Phil]

Hi together!
Right now I'm struggling with capturing when a user bookmarks a page.
Something along the lines of

// crude work-around
window.document.getElementById("Browser:AddBookmarkAs").addEventListener("command",
Foo.init, false);

does the job for bookmarking via Ctrl-D, but other means of
bookmarking - e.g. drag and drop to the bookmarks sidebar - can't be
detected. Does anybody out there know a more *generic* and elegant way
to listen to a bookmarking event? Thanks in advance!

Cheers, Phil