Hey you approximate five fvwm users on pdaX,
perhaps you are interested in a module that monitors the apm status.
I wrote it to replace a shell script which needed to much resources.
You can configure certain commands that are executed when the
battery/AC - status changes. Just look at the sample config
If you want to compile it:
Unpack the source within the modules directory of the fvwm source tree
and change the Makefile to your needs.