Thanks for your answer!.
I followed your instructions and now I have the batery manager of XFCE,
something very useful that gives me more control over it. But, sadly I still
can't change the volume with the Fn keys, the brightness notifications maybe
require the propietary driver of my graphic card, I had them when I installed
it in the non-free distro I was using before, but I can change it with Fn
keys.
I checked lubuntu 13.04 some time ago, and I liked the fact it was able to
generate thumbnails of videos, I hope to have that in my trisquel mini in a
near future XD.
By the way, if this is a bug where should I report it?.
