Hello, I'm trying to solve a similar issue with laptop-mode-tools in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=780956#30 (it hasn't worked so far, but it might be some race issue). What might be relevant to this bug (and the related ones like http://bugs.debian.org/725284) might be a prototype script for reusing existing pm-utils hooks attached in that message. It's a different approach than using udev, but at least it reuses existing code that is specifically designed for suspending. Just putting this here for your consideration.
Kind regards, Ondrej Grover
